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Dibus N, Salyova E, Kolarova K, Abdirov A, Pagano M, Stepanek O, Cermak L. FBXO38 is dispensable for PD-1 regulation. EMBO Rep 2024:10.1038/s44319-024-00220-8. [PMID: 39266770 DOI: 10.1038/s44319-024-00220-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 03/05/2024] [Accepted: 06/13/2024] [Indexed: 09/14/2024] Open
Abstract
SKP1-CUL1-F-box protein (SCF) ubiquitin ligases are versatile protein complexes that mediate the ubiquitination of protein substrates. The direct substrate recognition relies on a large family of F-box-domain-containing subunits. One of these substrate receptors is FBXO38, which is encoded by a gene found mutated in families with early-onset distal motor neuronopathy. SCFFBXO38 ubiquitin ligase controls the stability of ZXDB, a nuclear factor associated with the centromeric chromatin protein CENP-B. Loss of FBXO38 in mice results in growth retardation and defects in spermatogenesis characterized by deregulation of the Sertoli cell transcription program and compromised centromere integrity. Moreover, it was reported that SCFFBXO38 mediates the degradation of PD-1, a key immune-checkpoint inhibitor in T cells. Here, we have re-addressed the link between SCFFBXO38 and PD-1 proteolysis. Our data do not support the notion that SCFFBXO38 directly or indirectly controls the abundance and stability of PD-1 in T cells.
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Affiliation(s)
- Nikol Dibus
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Eva Salyova
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Karolina Kolarova
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Alikhan Abdirov
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Michele Pagano
- Department of Biochemistry and Molecular Pharmacology, Howard Hughes Medical Institute, Laura and Isaac Perlmutter NYU Cancer Center, New York University Grossman School of Medicine, New York, NY, 10016, USA.
| | - Ondrej Stepanek
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Lukas Cermak
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
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Saferali A, Kim W, Chase RP, Vollmers C, Silverman EK, Cho MH, Castaldi PJ, Hersh CP. Overlap between COPD genetic association results and transcriptional quantitative trait loci. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.07.08.24310079. [PMID: 39040180 PMCID: PMC11261918 DOI: 10.1101/2024.07.08.24310079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Rationale Genome-wide association studies (GWAS) have identified multiple genetic loci associated with chronic obstructive pulmonary disease (COPD). When integrated with GWAS results, expression quantitative trait locus (eQTL) studies can provide insight into biological mechanisms involved in disease by identifying single nucleotide polymorphisms (SNPs) that contribute to whole gene expression. However, there are multiple genetically driven regulatory and isoform-specific effects which cannot be detected in traditional eQTL analyses. Here, we identify SNPs that are associated with alternative splicing (sQTL) in addition to eQTLs to identify novel functions for COPD associated genetic variants. Methods We performed RNA sequencing on whole blood from 3743 subjects in the COPDGene Study. RNA sequencing data from lung tissue of 1241 subjects from the Lung Tissue Research Consortium (LTRC), and whole genome sequencing data on all subjects. Associations between all SNPs within 1000 kb of a gene (cis-) and splice and gene expression quantifications were tested using tensorQTL. In COPDGene a total of 11,869,333 SNPs were tested for association with 58,318 splice clusters, and 8,792,206 SNPs were tested for association with 70,094 splice clusters in LTRC. We assessed colocalization with COPD-associated SNPs from a published GWAS[1]. Results After adjustment for multiple statistical testing, we identified 28,110 splice-sites corresponding to 3,889 unique genes that were significantly associated with genotype in COPDGene whole blood, and 58,258 splice-sites corresponding to 10,307 unique genes associated with genotype in LTRC lung tissue. We found 7,576 sQTL splice-sites corresponding to 2,110 sQTL genes were shared between whole blood and lung, while 20,534 sQTL splice-sites in 3,518 genes were unique to blood and 50,682 splice-sites in 9,677 genes were unique to lung. To determine what proportion of COPD-associated SNPs were associated with transcriptional splicing, we performed colocalization analysis between COPD GWAS and sQTL data, and found that 38 genomic windows, corresponding to 38 COPD GWAS loci had evidence of colocalization between QTLs and COPD. The top five colocalizations between COPD and lung sQTLs include NPNT , FBXO38 , HHIP , NTN4 and BTC . Conclusions A total of 38 COPD GWAS loci contain evidence of sQTLs, suggesting that analysis of sQTLs in whole blood and lung tissue can provide novel insights into disease mechanisms.
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Wu Y, Lin Y, Shen F, Huang R, Zhang Z, Zhou M, Fang Y, Shen J, Fan X. FBXO38 deficiency promotes lysosome-dependent STING degradation and inhibits cGAS-STING pathway activation. Neoplasia 2024; 49:100973. [PMID: 38277817 PMCID: PMC10832482 DOI: 10.1016/j.neo.2024.100973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 01/11/2024] [Accepted: 01/18/2024] [Indexed: 01/28/2024]
Abstract
F-box only protein 38 (FBXO38) is a member of the F-box family that mediates the ubiquitination and proteasome degradation of programmed death 1 (PD-1), and thus has important effects on T cell-related immunity. While its powerful role in adaptive immunity has attracted much attention, its regulatory roles in innate immune pathways remain unknown. The cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is an important innate immune pathway that regulates type I interferons. STING protein is the core component of this pathway. In this study, we identified that FBXO38 deficiency enhanced tumor proliferation and reduced tumor CD8+ T cells infiltration. Loss of FBXO38 resulted in reduced STING protein levels in vitro and in vivo, further leading to preventing cGAS-STING pathway activation, and decreased downstream product IFNA1 and CCL5. The mechanism of reduced STING protein was associated with lysosome-mediated degradation rather than proteasomal function. Our results demonstrate a critical role for FBXO38 in the cGAS-STING pathway.
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Affiliation(s)
- Yijia Wu
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Yao Lin
- Institute of Translational Medicine, National Facility for Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Feiyang Shen
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Rui Huang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Zhe Zhang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China; Institute of Translational Medicine, National Facility for Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Min Zhou
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China
| | - Yan Fang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China.
| | - Jianfeng Shen
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China; Institute of Translational Medicine, National Facility for Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Xianqun Fan
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai 200025, China.
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Hong W, Gong P, Pan X, Liu Y, Qi G, Qi C, Qin S. Krüppel-like factor 7 deficiency disrupts corpus callosum development and neuronal migration in the developing mouse cerebral cortex. Brain Pathol 2023; 33:e13186. [PMID: 37401095 PMCID: PMC10467035 DOI: 10.1111/bpa.13186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 06/16/2023] [Indexed: 07/05/2023] Open
Abstract
Krüppel-like Factor 7 (KLF7) is a zinc finger transcription factor that has a critical role in cellular differentiation, tumorigenesis, and regeneration. Mutations in Klf7 are associated with autism spectrum disorder, which is characterized by neurodevelopmental delay and intellectual disability. Here we show that KLF7 regulates neurogenesis and neuronal migration during mouse cortical development. Conditional depletion of KLF7 in neural progenitor cells resulted in agenesis of the corpus callosum, defects in neurogenesis, and impaired neuronal migration in the neocortex. Transcriptomic profiling analysis indicated that KLF7 regulates a cohort of genes involved in neuronal differentiation and migration, including p21 and Rac3. These findings provide insights into our understanding of the potential mechanisms underlying neurological defects associated with Klf7 mutations.
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Affiliation(s)
- Wentong Hong
- Department of Anatomy, Histology and Embryology, School of Basic Medical SciencesFudan UniversityShanghaiChina
| | - Pifang Gong
- Department of Anatomy, Histology and Embryology, School of Basic Medical SciencesFudan UniversityShanghaiChina
| | - Xinjie Pan
- Department of Anatomy, Histology and Embryology, School of Basic Medical SciencesFudan UniversityShanghaiChina
| | - Yitong Liu
- Department of Anatomy, Histology and Embryology, School of Basic Medical SciencesFudan UniversityShanghaiChina
| | - Guibo Qi
- Department of Anatomy, Histology and Embryology, School of Basic Medical SciencesFudan UniversityShanghaiChina
| | - Congcong Qi
- Department of Laboratory Animal ScienceFudan UniversityShanghaiChina
| | - Song Qin
- Department of Anatomy, Histology and Embryology, School of Basic Medical SciencesFudan UniversityShanghaiChina
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain ScienceFudan UniversityShanghaiChina
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Krüppel-like Factor 7 inhibits proliferation and migration of pulmonary smooth muscle cells via p21 activation. Eur J Pharmacol 2023; 940:175473. [PMID: 36566916 DOI: 10.1016/j.ejphar.2022.175473] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
The aberrant proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) are critical contributors to the pulmonary vascular remodeling that occurs during the development of Pulmonary arterial hypertension (PAH). Krüppel-like Factor 7 (KLF7) has been reported to be involved in the development of certain cardiovascular diseases. However, the role of KLF7 in PAH remains unknown. Here, we aimed to explore whether KLF7 mediates the proliferation and migration of PASMCs and its underlying mechanism. In this study, Sprague Dawley rats were exposed to 60 mg/kg monocrotaline (MCT) for 3 weeks to induce PAH and human PASMCs were stimulated with 20 ng/ml platelet-derived growth factor-BB (PDGF-BB) for 24 h to induce proliferation and migration. The mRNA and protein expression of KLF7 were significantly down-regulated in MCT-induced PAH rats and PDGF-BB-treated PASMCs. Under normal conditions, KLF7 knockdown obviously promoted PASMCs proliferation and migration, whereas KLF7 overexpression exhibited the opposite effects. Furthermore, PDGF-BB promoted the PASMCs proliferation and migration, increased the cell proportion in S phase, which was significantly attenuated by overexpression of KLF7. Mechanistic investigation indicated that KLF7 through activation its target protein, the cell cycle inhibitor p21, which finally leading to the inhibition of PASMCs growth. Consistently, UC2288, a specific inhibitor of p21, partially reversed the PASMCs proliferation inhibited by KLF7 overexpression. Taken collectively, the data suggested that KLF7 inhibits PASMCs proliferation and migration via p21 pathway and it may be used as a new therapeutic target for the PAH.
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KLF7 promotes preadipocyte proliferation via activation of the Akt signaling pathway by Cis-regulating CDKN3. Acta Biochim Biophys Sin (Shanghai) 2022; 54:1486-1496. [PMID: 36269137 PMCID: PMC9827951 DOI: 10.3724/abbs.2022144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Krüppel-like transcription factor 7 (KLF7) promotes preadipocyte proliferation; however, its target gene in this process has not yet been identified. Using KLF7 ChIP-seq analysis, we previously showed that a KLF7-binding peak is present upstream of the cyclin-dependent kinase inhibitor 3 gene ( CDKN3) in chicken preadipocytes. In the present study, we identify CDKN3 as a target gene of KLF7 that mediates the effects of KLF7 on preadipocyte proliferation. Furthermore, 5'-truncating mutation analysis shows that the minimal promoter is located between nt -160 and nt -7 (relative to the translation initiation codon ATG) of CDKN3. KLF7 overexpression increases CDKN3 promoter activity in the DF-1 and immortalized chicken preadipocyte (ICP1) cell lines. Deletion of the putative binding site of KLF7 abolishes the promotive effect of KLF7 overexpression on CDKN3 promoter activity. Moreover, CDKN3 knockdown and overexpression assays reveal that CDKN3 enhances ICP1 cell proliferation. Flow cytometry analysis shows that CDKN3 accelerates the G1/S transition. Furthermore, we find that KLF7 promotes ICP1 cell proliferation via Akt phosphorylation by regulating CDKN3. Taken together, our results suggest that KLF7 promotes preadipocyte proliferation by activating the Akt signaling pathway by cis-regulating CDKN3, thus driving the G1/S transition.
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Dibus N, Korinek V, Cermak L. FBXO38 Ubiquitin Ligase Controls Centromere Integrity via ZXDA/B Stability. Front Cell Dev Biol 2022; 10:929288. [PMID: 35813202 PMCID: PMC9260856 DOI: 10.3389/fcell.2022.929288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022] Open
Abstract
Alterations in the gene encoding the E3 ubiquitin ligase substrate receptor FBXO38 have been associated with several diseases, including early-onset motor neuronopathy. However, the cellular processes affected by the enzymatic action of FBXO38 are not yet known. Here, we identify the zinc finger proteins ZXDA/B as its interaction partners. FBXO38 controls the stability of ZXDA/B proteins via ubiquitination and proteasome-dependent degradation. We show that ZXDA/B proteins associate with the centromeric protein CENP-B and that the interaction between ZXDA/B and FBXO38 or CENP-B is mutually exclusive. Functionally, ZXDA/B factors control the protein level of chromatin-associated CENP-B. Furthermore, their inappropriate stabilization leads to upregulation of CENP-A and CENP-B positive centromeric chromatin. Thus we demonstrate a previously unknown role of cullin-dependent protein degradation in the control of centromeric chromatin integrity.
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Affiliation(s)
- Nikol Dibus
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
| | - Vladimir Korinek
- Laboratory of Cell and Developmental Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Lukas Cermak
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
- *Correspondence: Lukas Cermak,
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Dibus N, Zobalova E, Monleon MAM, Korinek V, Filipp D, Petrusova J, Sedlacek R, Kasparek P, Cermak L. FBXO38 Ubiquitin Ligase Controls Sertoli Cell Maturation. Front Cell Dev Biol 2022; 10:914053. [PMID: 35769260 PMCID: PMC9234700 DOI: 10.3389/fcell.2022.914053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/19/2022] [Indexed: 12/18/2022] Open
Abstract
The ubiquitin ligase SCFFBXO38 controls centromeric chromatin by promoting the degradation of the ZXDB protein. To determine the importance of this pathway during development, Fbxo38-deficient mice were generated. The loss of FBXO38 resulted in growth retardation affecting several organs, including the male reproductive system. A detailed analysis of the mutant testes revealed pathological changes in the seminiferous tubules, accompanied by a significant decrease in sperm production and reduced fertility. In adult testes, FBXO38 was specifically expressed in Sertoli cells, a somatic population essential for spermatogenesis initiation and progression. Sertoli cells lacking FBXO38 exhibited stabilized ZXDB protein and upregulated centromeric chromatin. Furthermore, the gene expression profile revealed that the absence of FBXO38 led to a defect in Sertoli cell maturation, specifically characterized by dysregulation in genes controlling retinoic acid metabolism and intercellular communication. Consequently, we documented significant changes in their ability to initiate spermatogonial differentiation. In conclusion, we show that FBXO38 acts as a Sertoli cell maturation factor, affecting the Sertoli cell transcription program, centromere integrity, and, subsequently, the ability to control spermatogenesis.
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Affiliation(s)
- Nikol Dibus
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
- Faculty of Science, Charles University, Prague, Czechia
| | - Eliska Zobalova
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
| | - Mario A. M. Monleon
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
| | - Vladimir Korinek
- Laboratory of Cell and Developmental Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Dominik Filipp
- Laboratory of Immunobiology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Jana Petrusova
- Laboratory of Immunobiology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Radislav Sedlacek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
| | - Petr Kasparek
- Czech Centre for Phenogenomics, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
| | - Lukas Cermak
- Laboratory of Cancer Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Vestec, Czechia
- *Correspondence: Lukas Cermak,
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Obesity-induced elevated palmitic acid promotes inflammation and glucose metabolism disorders through GPRs/NF-κB/KLF7 pathway. Nutr Diabetes 2022; 12:23. [PMID: 35443706 PMCID: PMC9021212 DOI: 10.1038/s41387-022-00202-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 03/18/2022] [Accepted: 04/07/2022] [Indexed: 01/15/2023] Open
Abstract
Objective Our previous results have shown that obesity-induced excessive palmitic acid (PA) can promote the expression of KLF7, which plays a vital role in regulation of inflammation, glucose metabolism. But the exact mechanism of PA up-regulating the expression of KLF7 is not clear yet. This study is intend to explore whether PA promoting KLF7 expression through GPRs/NF-κB signaling pathway, causing inflammation and glucose metabolism disorders. Methods Cells were blocked GPRs/NF-κB under PA stimulation in vitro to demonstrate the molecular mechanism of PA up-regulates KLF7 expression. The regulatory effect of p65 on KLF7 was detected by luciferase reporter gene assay. Blocking GPRs/NF-κB in diet-induced obesity mice to detect the expression of KLF7, inflammatory cytokines and glucose metabolism related factors, clarifying the effects of GPRs/NF-κB on KLF7 in vivo. Results In 3T3-L1 adipocytes and HepG2 cells, PA could up-regulate the expression of KLF7 by promoting the GPR40/120-NF-κB signaling pathway, leading to inflammation and reduced glucose consumption (p < 0.05 for both). Luciferase reporter gene assay and ChIP assay showed that p65 could transcriptionally up-regulates the expression of KLF7. In high-fat diet (HFD) mice, after intraperitoneal injection of GPR40 or GPR120 blocker, the levels of p-p65 and KLF7 in epididymal white adipose tissue and liver were significantly decreased (p < 0.05 for both). Pharmacological inhibition of p-p65 significantly attenuated KLF7 expression and improved glucose tolerant and insulin sensitive (p < 0.05 for both). Conclusions Our results indicate that obesity-induced elevated palmitic acid promotes inflammation and glucose metabolism disorders through GPRs/NF-κB/KLF7 signaling pathway.
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Krüppel-like Transcription Factor 7 Is a Causal Gene in Autism Development. Int J Mol Sci 2022; 23:ijms23063376. [PMID: 35328799 PMCID: PMC8949233 DOI: 10.3390/ijms23063376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/13/2022] [Accepted: 03/18/2022] [Indexed: 01/27/2023] Open
Abstract
Background: Autism spectrum disorder (ASD) is a complex neurodevelopmental disease. To date, more than 1000 genes have been shown to be associated with ASD, and only a few of these genes account for more than 1% of autism cases. Klf7 is an important transcription factor of cell proliferation and differentiation in the nervous system, but whether klf7 is involved in autism is unclear. Methods: We first performed ChIP-seq analysis of klf7 in N2A cells, then performed behavioral tests and RNA-seq in klf7+/− mice, and finally restored mice with adeno-associated virus (AAV)-mediated overexpression of klf7 in klf7+/− mice. Results: Klf7 targeted genes are enriched with ASD genes, and 631 ASD risk genes are also differentially expressed in klf7+/− mice which exhibited the core symptoms of ASD. When klf7 levels were increased in the central nervous system (CNS) in klf7+/− adult mice, deficits in social interaction, repetitive behavior and majority of dysregulated ASD genes were rescued in the adults, suggesting transcriptional regulation. Moreover, knockdown of klf7 in human brain organoids caused dysregulation of 517 ASD risk genes, 344 of which were shared with klf7+/− mice, including some high-confidence ASD genes. Conclusions: Our findings highlight a klf7 regulation of ASD genes and provide new insights into the pathogenesis of ASD and promising targets for further research on mechanisms and treatments.
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Beijer D, Baets J. The expanding genetic landscape of hereditary motor neuropathies. Brain 2021; 143:3540-3563. [PMID: 33210134 DOI: 10.1093/brain/awaa311] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Hereditary motor neuropathies are clinically and genetically diverse disorders characterized by length-dependent axonal degeneration of lower motor neurons. Although currently as many as 26 causal genes are known, there is considerable missing heritability compared to other inherited neuropathies such as Charcot-Marie-Tooth disease. Intriguingly, this genetic landscape spans a discrete number of key biological processes within the peripheral nerve. Also, in terms of underlying pathophysiology, hereditary motor neuropathies show striking overlap with several other neuromuscular and neurological disorders. In this review, we provide a current overview of the genetic spectrum of hereditary motor neuropathies highlighting recent reports of novel genes and mutations or recent discoveries in the underlying disease mechanisms. In addition, we link hereditary motor neuropathies with various related disorders by addressing the main affected pathways of disease divided into five major processes: axonal transport, tRNA aminoacylation, RNA metabolism and DNA integrity, ion channels and transporters and endoplasmic reticulum.
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Affiliation(s)
- Danique Beijer
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
| | - Jonathan Baets
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Belgium
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Blondelle J, Biju A, Lange S. The Role of Cullin-RING Ligases in Striated Muscle Development, Function, and Disease. Int J Mol Sci 2020; 21:E7936. [PMID: 33114658 PMCID: PMC7672578 DOI: 10.3390/ijms21217936] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/11/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
The well-orchestrated turnover of proteins in cross-striated muscles is one of the fundamental processes required for muscle cell function and survival. Dysfunction of the intricate protein degradation machinery is often associated with development of cardiac and skeletal muscle myopathies. Most muscle proteins are degraded by the ubiquitin-proteasome system (UPS). The UPS involves a number of enzymes, including E3-ligases, which tightly control which protein substrates are marked for degradation by the proteasome. Recent data reveal that E3-ligases of the cullin family play more diverse and crucial roles in cross striated muscles than previously anticipated. This review highlights some of the findings on the multifaceted functions of cullin-RING E3-ligases, their substrate adapters, muscle protein substrates, and regulatory proteins, such as the Cop9 signalosome, for the development of cross striated muscles, and their roles in the etiology of myopathies.
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Affiliation(s)
- Jordan Blondelle
- Department of Medicine, University of California, La Jolla, CA 92093, USA
| | - Andrea Biju
- Department of Medicine, University of California, La Jolla, CA 92093, USA
| | - Stephan Lange
- Department of Medicine, University of California, La Jolla, CA 92093, USA
- Department of Molecular and Clinical Medicine, University of Gothenburg, 41345 Gothenburg, Sweden
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Zhang Z, Wu C, Lin T, Chen Y. Loss of the third C2H2 zinc finger of chicken KLF7 affects its transcriptional regulation activities in adipose tissue. Acta Biochim Biophys Sin (Shanghai) 2020; 52:84-90. [PMID: 31828306 DOI: 10.1093/abbs/gmz132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 09/19/2019] [Accepted: 10/18/2019] [Indexed: 11/13/2022] Open
Abstract
KLF7, one of candidate genes in neurotherapy and metabolic syndrome, has been studied in adipogenesis of mammalian species and birds. However, the effect of the third C2H2 zinc finger of KLF7 for its transcriptional regulation in adipogenesis has not been well understood. Here, the wild-type chicken KLF7 (KLF7) overexpression plasmid, pCMV-myc-KLF7, and two plasmids of chicken KLF7 mutants, i.e. pCMV-myc-KLF7m1 with half of the third zinc finger (KLF7m1) and pCMV-myc-KLF7m2 without the third zinc finger (KLF7m2), were constructed. Luciferase reporter assay in DF1 cells showed that the effect of chicken KLF7 overexpression on the promoter activity of LPL was greater than those of KLF7m1 and KLF7m2 (P < 0.05). There was no significant difference among the overexpression of KLF7, KLF7m1 and KLF7m2 on the promoter activities of FASN, C/EBPα and FABP4 (P > 0.05). Additionally, the effects of KLF7, KLF7m1 and KLF7m2 overexpression on the promoter activity of PPARγ were different. KLF7 overexpression had no significant effect on the PPARγ promoter activity (P > 0.05), KLF7m1 overexpression suppressed PPARγ promoter activity (P < 0.05), while KLF7m2 overexpression facilitated the promoter activity of PPARγ (P < 0.05), consistent with the results of western blot analysis. Our results suggested that the third zinc finger of chicken KLF7 may play a role in its transcriptional regulation of LPL and PPARγ but has no effect on its regulation of C/EBPα, FASN and FABP4. The third zinc finger of KLF7 might be a target for the treatment of metabolic disorder in chicken.
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Affiliation(s)
- Zhiwei Zhang
- School of Medicine, Shihezi University, Shihezi 832000, China
| | - Chunyan Wu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
| | - Tao Lin
- School of Medicine, Shihezi University, Shihezi 832000, China
| | - Yuechan Chen
- First Affiliated Hospital of School of Medicine, Shihezi University, Shihezi 832000, China
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14
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Analysis of genetically driven alternative splicing identifies FBXO38 as a novel COPD susceptibility gene. PLoS Genet 2019; 15:e1008229. [PMID: 31269066 PMCID: PMC6634423 DOI: 10.1371/journal.pgen.1008229] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 07/16/2019] [Accepted: 06/04/2019] [Indexed: 11/19/2022] Open
Abstract
While many disease-associated single nucleotide polymorphisms (SNPs) are associated with gene expression (expression quantitative trait loci, eQTLs), a large proportion of complex disease genome-wide association study (GWAS) variants are of unknown function. Some of these SNPs may contribute to disease by regulating gene splicing. Here, we investigate whether SNPs that are associated with alternative splicing (splice QTL or sQTL) can identify novel functions for existing GWAS variants or suggest new associated variants in chronic obstructive pulmonary disease (COPD). RNA sequencing was performed on whole blood from 376 subjects from the COPDGene Study. Using linear models, we identified 561,060 unique sQTL SNPs associated with 30,333 splice sites corresponding to 6,419 unique genes. Similarly, 708,928 unique eQTL SNPs involving 15,913 genes were detected at 10% FDR. While there is overlap between sQTLs and eQTLs, 55.3% of sQTLs are not eQTLs. Co-localization analysis revealed that 7 out of 21 loci associated with COPD (p<1x10-6) in a published GWAS have at least one shared causal variant between the GWAS and sQTL studies. Among the genes identified to have splice sites associated with top GWAS SNPs was FBXO38, in which a novel exon was discovered to be protective against COPD. Importantly, the sQTL in this locus was validated by qPCR in both blood and lung tissue, demonstrating that splice variants relevant to lung tissue can be identified in blood. Other identified genes included CDK11A and SULT1A2. Overall, these data indicate that analysis of alternative splicing can provide novel insights into disease mechanisms. In particular, we demonstrated that SNPs in a known COPD GWAS locus on chromosome 5q32 influence alternative splicing in the gene FBXO38.
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15
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Zyla J, Kabacik S, O'Brien G, Wakil S, Al-Harbi N, Kaprio J, Badie C, Polanska J, Alsbeih G. Combining CDKN1A gene expression and genome-wide SNPs in a twin cohort to gain insight into the heritability of individual radiosensitivity. Funct Integr Genomics 2019; 19:575-585. [PMID: 30706161 PMCID: PMC6570669 DOI: 10.1007/s10142-019-00658-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/12/2018] [Accepted: 01/09/2019] [Indexed: 12/15/2022]
Abstract
Individual variability in response to radiation exposure is recognised and has often been reported as important in treatment planning. Despite many efforts to identify biomarkers allowing the identification of radiation sensitive patients, it is not yet possible to distinguish them with certainty before the beginning of the radiotherapy treatment. A comprehensive analysis of genome-wide single-nucleotide polymorphisms (SNPs) and a transcriptional response to ionising radiation exposure in twins have the potential to identify such an individual. In the present work, we investigated SNP profile and CDKN1A gene expression in blood T lymphocytes from 130 healthy Caucasians with a complex level of individual kinship (unrelated, mono- or dizygotic twins). It was found that genetic variation accounts for 66% (95% CI 37-82%) of CDKN1A transcriptional response to radiation exposure. We developed a novel integrative multi-kinship strategy allowing investigating the role of genome-wide polymorphisms in transcriptomic radiation response, and it revealed that rs205543 (ETV6 gene), rs2287505 and rs1263612 (KLF7 gene) are significantly associated with CDKN1A expression level. The functional analysis revealed that rs6974232 (RPA3 gene), involved in mismatch repair (p value = 9.68e-04) as well as in RNA repair (p value = 1.4e-03) might have an important role in that process. Two missense polymorphisms with possible deleterious effect in humans were identified: rs1133833 (AKIP1 gene) and rs17362588 (CCDC141 gene). In summary, the data presented here support the validity of this novel integrative data analysis strategy to provide insights into the identification of SNPs potentially influencing radiation sensitivity. Further investigations in radiation response research at the genomic level should be therefore continued to confirm these findings.
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Affiliation(s)
- Joanna Zyla
- Data Mining Division, Faculty of Automatic Control, Electronic and Computer Science, Silesian University of Technology, Akademicka 16, 44-100, Gliwice, Poland
| | - Sylwia Kabacik
- Cellular Biology Group, Radiation Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, UK
| | - Grainne O'Brien
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, UK
| | - Salma Wakil
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Kingdom of Saudi Arabia
| | - Najla Al-Harbi
- Radiation Biology Section, Biomedical Physics Department, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Kingdom of Saudi Arabia
| | - Jaakko Kaprio
- Department of Public Health and Institute for Molecular Medicine FIMM, University of Helsinki, 00140, Helsinki, Finland
| | - Christophe Badie
- Cancer Mechanisms and Biomarkers Group, Radiation Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, OX11 0RQ, UK
| | - Joanna Polanska
- Data Mining Division, Faculty of Automatic Control, Electronic and Computer Science, Silesian University of Technology, Akademicka 16, 44-100, Gliwice, Poland.
| | - Ghazi Alsbeih
- Radiation Biology Section, Biomedical Physics Department, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Kingdom of Saudi Arabia
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Baptista CG, Lis A, Deng B, Gas-Pascual E, Dittmar A, Sigurdson W, West CM, Blader IJ. Toxoplasma F-box protein 1 is required for daughter cell scaffold function during parasite replication. PLoS Pathog 2019; 15:e1007946. [PMID: 31348812 PMCID: PMC6685633 DOI: 10.1371/journal.ppat.1007946] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 08/07/2019] [Accepted: 06/27/2019] [Indexed: 01/06/2023] Open
Abstract
By binding to the adaptor protein SKP1 and serving as substrate receptors for the SKP1 Cullin, F-box E3 ubiquitin ligase complex, F-box proteins regulate critical cellular processes including cell cycle progression and membrane trafficking. While F-box proteins are conserved throughout eukaryotes and are well studied in yeast, plants, and animals, studies in parasitic protozoa are lagging. We have identified eighteen putative F-box proteins in the Toxoplasma genome of which four have predicted homologs in Plasmodium. Two of the conserved F-box proteins were demonstrated to be important for Toxoplasma fitness and here we focus on an F-box protein, named TgFBXO1, because it is the most highly expressed by replicative tachyzoites and was also identified in an interactome screen as a Toxoplasma SKP1 binding protein. TgFBXO1 interacts with Toxoplasma SKP1 confirming it as a bona fide F-box protein. In interphase parasites, TgFBXO1 is a component of the Inner Membrane Complex (IMC), which is an organelle that underlies the plasma membrane. Early during replication, TgFBXO1 localizes to the developing daughter cell scaffold, which is the site where the daughter cell IMC and microtubules form and extend from. TgFBXO1 localization to the daughter cell scaffold required centrosome duplication but before kinetochore separation was completed. Daughter cell scaffold localization required TgFBXO1 N-myristoylation and was dependent on the small molecular weight GTPase, TgRab11b. Finally, we demonstrate that TgFBXO1 is required for parasite growth due to its function as a daughter cell scaffold effector. TgFBXO1 is the first F-box protein to be studied in apicomplexan parasites and represents the first protein demonstrated to be important for daughter cell scaffold function.
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Affiliation(s)
- Carlos Gustavo Baptista
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Agnieszka Lis
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Bowen Deng
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Elisabet Gas-Pascual
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Ashley Dittmar
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Wade Sigurdson
- Department of Physiology and Biophysics, University at Buffalo School of Medicine, Buffalo, New York, United States of America
| | - Christopher M. West
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Ira J. Blader
- Department of Microbiology and Immunology, University at Buffalo School of Medicine, Buffalo, New York, United States of America
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17
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Sugiyama S, Yumimoto K, Inoue I, Nakayama KI. SCF
Fbxw7
ubiquitylates KLF7 for degradation in a manner dependent on GSK‐3‐mediated phosphorylation. Genes Cells 2019; 24:354-365. [DOI: 10.1111/gtc.12680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/01/2019] [Accepted: 03/03/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Shigeaki Sugiyama
- Department of Molecular and Cellular Biology Medical Institute of Bioregulation, Kyushu University Fukuoka Japan
| | - Kanae Yumimoto
- Department of Molecular and Cellular Biology Medical Institute of Bioregulation, Kyushu University Fukuoka Japan
| | - Ippei Inoue
- Department of Molecular and Cellular Biology Medical Institute of Bioregulation, Kyushu University Fukuoka Japan
| | - Keiichi I. Nakayama
- Department of Molecular and Cellular Biology Medical Institute of Bioregulation, Kyushu University Fukuoka Japan
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18
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Georges A, Coyaud E, Marcon E, Greenblatt J, Raught B, Frappier L. USP7 Regulates Cytokinesis through FBXO38 and KIF20B. Sci Rep 2019; 9:2724. [PMID: 30804394 PMCID: PMC6389929 DOI: 10.1038/s41598-019-39368-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 01/18/2019] [Indexed: 01/13/2023] Open
Abstract
The ubiquitin specific protease 7 (USP7 or HAUSP) is known to regulate a variety of cellular processes by binding and deubiquitylating specific target proteins. To gain a more comprehensive understanding of its interactions and functions, we used affinity purification coupled to mass spectrometry to profile USP7 interactions. This revealed a novel interaction with FBXO38, a poorly characterized F-box protein. We showed that USP7 stabilizes FBXO38 dependent on its catalytic activity by protecting FBXO38 from proteasomal degradation. We used a BioID approach to profile the protein interactions (and putative functions) of FBXO38, revealing an interaction with KIF20B, a Kinesin-6 protein required for efficient cytokinesis. FBXO38 was shown to function independently from an SCF complex to stabilize KIF20B. Consequently, depletion of either FBXO38 or USP7 led to dramatic decreases in KIF20B levels and KIF20B at the midbody, which were manifested in cytokinetic defects. Furthermore, cytokinetic defects associated with USP7 silencing were rescued by restoring FBXO38 or KIF20B. The results indicate a novel mechanism of regulating cytokinesis through USP7 and FBXO38.
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Affiliation(s)
- Anna Georges
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Etienne Coyaud
- The Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, M5G 1L7, Canada
| | - Edyta Marcon
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Jack Greenblatt
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Donnelly Centre, University of Toronto, Toronto, Canada
| | - Brian Raught
- The Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Lori Frappier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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19
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The Effect and Mechanism of KLF7 in the TLR4/NF- κB/IL-6 Inflammatory Signal Pathway of Adipocytes. Mediators Inflamm 2018; 2018:1756494. [PMID: 30598636 PMCID: PMC6287150 DOI: 10.1155/2018/1756494] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 08/20/2018] [Accepted: 09/19/2018] [Indexed: 01/07/2023] Open
Abstract
Objective To investigate the role and possible molecular mechanism of Krüppel-like factor 7 (KLF7) in the TLR4/NF-κB/IL-6 inflammatory signaling pathway activated by free fatty acids (FFA). Methods The mRNA and protein expression levels of KLF7 and the factors of TLR4/NF-κB/IL-6 inflammatory signal pathways were detected by qRT-PCR and Western blotting after cell culture with different concentrations of palmitic acid (PA). The expression of KLF7 or TLR4 in adipocytes was upregulated or downregulated; after that, the mRNA and protein expression levels of these key factors were detected. KLF7 expression was downregulated while PA stimulated adipocytes, and then the mRNA and protein expressions of KLF7/p65 and downstream inflammatory cytokine IL-6 were detected. The luciferase reporter assay was used to determine whether KLF7 had a transcriptional activation effect on IL-6. Results (1) High concentration of PA can promote the expression of TLR4, KLF7, and IL-6 in adipocytes. (2) TLR4 positively regulates KLF7 expression in adipocytes. (3) KLF7 positively regulates IL-6 expression in adipocytes. (4) PA promotes IL-6 expression via KLF7 in adipocytes. (5) KLF7 has a transcriptional activation on IL-6. Conclusion PA promotes the expression of the inflammatory cytokine IL-6 by activating the TLR4/KLF7/NF-κB inflammatory signaling pathway. In addition, KLF7 may directly bind to the IL-6 promoter region and thus activate IL-6.
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20
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Wang X, Shen QW, Wang J, Zhang Z, Feng F, Chen T, Zhang Y, Wei H, Li Z, Wang X, Wang Y. KLF7 Regulates Satellite Cell Quiescence in Response to Extracellular Signaling. Stem Cells 2016; 34:1310-20. [PMID: 26930448 DOI: 10.1002/stem.2346] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 11/12/2015] [Indexed: 11/11/2022]
Abstract
Retaining muscle stem satellite cell (SC) quiescence is important for the maintenance of stem cell population and tissue regeneration. Accumulating evidence supports the model where key extracellular signals play crucial roles in maintaining SC quiescence or activation, however, the intracellular mechanisms that mediate niche signals to control SC behavior are not fully understood. Here, we reported that KLF7 functioned as a key mediator involved in low-level TGF-β signaling and canonical Notch signaling-induced SC quiescence and myoblast arrest. The data obtained showed that KLF7 was upregulated in quiescent SCs and nonproliferating myoblasts. Silence of KLF7 promoted SCs activation and myoblasts proliferation, but overexpression of KLF7 induced myogenic cell arrest. Notably, the expression of KLF7 was regulated by TGF-β and Notch3 signaling. Knockdown of KLF7 diminished low-level TGF-β and canonical Notch signaling-induced SC quiescence. Investigation into the mechanism revealed that KLF7 regulation of SC function was dependent on p21 and acetylation of Lys227 and/or 231 in the DNA binding domain of KLF7. Our study provides new insights into the regulatory network of muscle stem cell quiescence. Stem Cells 2016;34:1310-1320.
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Affiliation(s)
- Xiaobin Wang
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Qingwu W Shen
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China.,College of Food Science and Technology, Hunan Agricultural University, Changsha, Hunan, People's Republic of China
| | - Jie Wang
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Zhiguo Zhang
- College of Food Science and Engineering, Qilu University of Technology, Jinan, Shandong, People's Republic of China
| | - Fu Feng
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Ting Chen
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Yanyan Zhang
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Huan Wei
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Zhongwen Li
- Department of Animal Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Xinxia Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Yizhen Wang
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
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21
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Hey bHLH Proteins Interact with a FBXO45 Containing SCF Ubiquitin Ligase Complex and Induce Its Translocation into the Nucleus. PLoS One 2015; 10:e0130288. [PMID: 26068074 PMCID: PMC4466309 DOI: 10.1371/journal.pone.0130288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 05/18/2015] [Indexed: 02/02/2023] Open
Abstract
The Hey protein family, comprising Hey1, Hey2 and HeyL in mammals, conveys Notch signals in many cell types. The helix-loop-helix (HLH) domain as well as the Orange domain, mediate homo- and heterodimerization of these transcription factors. Although distinct interaction partners have been identified so far, their physiological relevance for Hey functions is still largely unclear. Using a tandem affinity purification approach and mass spectrometry analysis we identified members of an ubiquitin E3-ligase complex consisting of FBXO45, PAM and SKP1 as novel Hey1 associated proteins. There is a direct interaction between Hey1 and FBXO45, whereas FBXO45 is needed to mediate indirect Hey1 binding to SKP1. Expression of Hey1 induces translocation of FBXO45 and PAM into the nucleus. Hey1 is a short-lived protein that is degraded by the proteasome, but there is no evidence for FBXO45-dependent ubiquitination of Hey1. On the contrary, Hey1 mediated nuclear translocation of FBXO45 and its associated ubiquitin ligase complex may extend its spectrum to additional nuclear targets triggering their ubiquitination. This suggests a novel mechanism of action for Hey bHLH factors.
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22
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Oren Y, Nachshon A, Frishberg A, Wilentzik R, Gat-Viks I. Linking traits based on their shared molecular mechanisms. eLife 2015; 4. [PMID: 25781485 PMCID: PMC4362207 DOI: 10.7554/elife.04346] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 02/20/2015] [Indexed: 12/29/2022] Open
Abstract
There is growing recognition that co-morbidity and co-occurrence of disease traits are often determined by shared genetic and molecular mechanisms. In most cases, however, the specific mechanisms that lead to such trait-trait relationships are yet unknown. Here we present an analysis of a broad spectrum of behavioral and physiological traits together with gene-expression measurements across genetically diverse mouse strains. We develop an unbiased methodology that constructs potentially overlapping groups of traits and resolves their underlying combination of genetic loci and molecular mechanisms. For example, our method predicts that genetic variation in the Klf7 gene may influence gene transcripts in bone marrow-derived myeloid cells, which in turn affect 17 behavioral traits following morphine injection; this predicted effect of Klf7 is consistent with an in vitro perturbation of Klf7 in bone marrow cells. Our analysis demonstrates the utility of studying hidden causative mechanisms that lead to relationships between complex traits.
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Affiliation(s)
- Yael Oren
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Aharon Nachshon
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Amit Frishberg
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Roni Wilentzik
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Irit Gat-Viks
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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23
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Fagoe ND, van Heest J, Verhaagen J. Spinal cord injury and the neuron-intrinsic regeneration-associated gene program. Neuromolecular Med 2014; 16:799-813. [PMID: 25269879 DOI: 10.1007/s12017-014-8329-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/20/2014] [Indexed: 12/14/2022]
Abstract
Spinal cord injury (SCI) affects millions of people worldwide and causes a significant physical, emotional, social and economic burden. The main clinical hallmark of SCI is the permanent loss of motor, sensory and autonomic function below the level of injury. In general, neurons of the central nervous system (CNS) are incapable of regeneration, whereas injury to the peripheral nervous system is followed by axonal regeneration and usually results in some degree of functional recovery. The weak neuron-intrinsic regeneration-associated gene (RAG) response upon injury is an important reason for the failure of neurons in the CNS to regenerate an axon. This response consists of the expression of many RAGs, including regeneration-associated transcription factors (TFs). Regeneration-associated TFs are potential key regulators of the RAG program. The function of some regeneration-associated TFs has been studied in transgenic and knock-out mice and by adeno-associated viral vector-mediated overexpression in injured neurons. Here, we review these studies and propose that AAV-mediated gene delivery of combinations of regeneration-associated TFs is a potential strategy to activate the RAG program in injured CNS neurons and achieve long-distance axon regeneration.
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Affiliation(s)
- Nitish D Fagoe
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, an Institute of the Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands,
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24
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Sumner C, d’Ydewalle C, Wooley J, Fawcett K, Hernandez D, Gardiner A, Kalmar B, Baloh R, Gonzalez M, Züchner S, Stanescu H, Kleta R, Mankodi A, Cornblath D, Boylan K, Reilly M, Greensmith L, Singleton A, Harms M, Rossor A, Houlden H. A dominant mutation in FBXO38 causes distal spinal muscular atrophy with calf predominance. Am J Hum Genet 2013; 93:976-83. [PMID: 24207122 PMCID: PMC3824115 DOI: 10.1016/j.ajhg.2013.10.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/03/2013] [Accepted: 10/04/2013] [Indexed: 11/19/2022] Open
Abstract
Spinal muscular atrophies (SMAs) are a heterogeneous group of inherited disorders characterized by degeneration of anterior horn cells and progressive muscle weakness. In two unrelated families affected by a distinct form of autosomal-dominant distal SMA initially manifesting with calf weakness, we identified by genetic linkage analysis and exome sequencing a heterozygous missense mutation, c.616T>C (p.Cys206Arg), in F-box protein 38 (FBXO38). FBXO38 is a known coactivator of the transcription factor Krüppel-like factor 7 (KLF7), which regulates genes required for neuronal axon outgrowth and repair. The p.Cys206Arg substitution did not alter the subcellular localization of FBXO38 but did impair KLF7-mediated transactivation of a KLF7-responsive promoter construct and endogenous KLF7 target genes in both heterologously expressing human embryonic kidney 293T cells and fibroblasts derived from individuals with the FBXO38 missense mutation. This transcriptional dysregulation was associated with an impairment of neurite outgrowth in primary motor neurons. Together, these results suggest that a transcriptional regulatory pathway that has a well-established role in axonal development could also be critical for neuronal maintenance and highlight the importance of FBXO38 and KLF7 activity in motor neurons.
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Affiliation(s)
- Charlotte J. Sumner
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Constantin d’Ydewalle
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Laboratory for Neurobiology, Vesalius Research Center, VIB and KU Leuven, 3000 Leuven, Belgium
| | - Joe Wooley
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Katherine A. Fawcett
- Department of Molecular Neuroscience, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Dena Hernandez
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alice R. Gardiner
- Department of Molecular Neuroscience, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Bernadett Kalmar
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Robert H. Baloh
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90095, USA
| | - Michael Gonzalez
- Dr. John T. MacDonald Department of Human Genetics and Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, FL 33136, USA
| | - Stephan Züchner
- Dr. John T. MacDonald Department of Human Genetics and Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, FL 33136, USA
| | - Horia C. Stanescu
- Center for Nephrology, University College London, London WC1N 3BG, UK
| | - Robert Kleta
- Center for Nephrology, University College London, London WC1N 3BG, UK
| | - Ami Mankodi
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - David R. Cornblath
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Kevin B. Boylan
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Mary M. Reilly
- Department of Molecular Neuroscience, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Linda Greensmith
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Andrew B. Singleton
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew B. Harms
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alexander M. Rossor
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- The MRC Centre for Neuromuscular Diseases, The National Hospital for Neurology and Neurosurgery and UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Nelson DE, Randle SJ, Laman H. Beyond ubiquitination: the atypical functions of Fbxo7 and other F-box proteins. Open Biol 2013; 3:130131. [PMID: 24107298 PMCID: PMC3814724 DOI: 10.1098/rsob.130131] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
F-box proteins (FBPs) are substrate-recruiting subunits of Skp1-cullin1-FBP (SCF)-type E3 ubiquitin ligases. To date, 69 FBPs have been identified in humans, but ubiquitinated substrates have only been identified for a few, with the majority of FBPs remaining ‘orphans’. In recent years, a growing body of work has identified non-canonical, SCF-independent roles for about 12% of the human FBPs. These atypical FBPs affect processes as diverse as transcription, cell cycle regulation, mitochondrial dynamics and intracellular trafficking. Here, we provide a general review of FBPs, with a particular emphasis on these expanded functions. We review Fbxo7 as an exemplar of this special group as it has well-defined roles in both SCF and non-SCF complexes. We review its function as a cell cycle regulator, via its ability to stabilize p27 protein and Cdk6 complexes, and as a proteasome regulator, owing to its high affinity binding to PI31. We also highlight recent advances in our understanding of Fbxo7 function in Parkinson's disease, where it functions in the regulation of mitophagy with PINK1 and Parkin. We postulate that a few extraordinary FBPs act as platforms that seamlessly segue their canonical and non-canonical functions to integrate different cellular pathways and link their regulation.
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Affiliation(s)
- David E Nelson
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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26
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Zhang ZW, Wang ZP, Zhang K, Wang N, Li H. Cloning, tissue expression and polymorphisms of chicken Krüppel-like factor 7 gene. Anim Sci J 2013; 84:535-42. [PMID: 23607628 DOI: 10.1111/asj.12043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 12/04/2012] [Indexed: 11/28/2022]
Abstract
Krüppel-like factor 7 (KLF7) has been extensively studied in mammalian species, but its role in birds is still unclear. In the current study, cloning and sequencing showed that the full-length coding region of chicken KLF7 (Gallus gallus KLF7, gKLF7) was 891 bp long, encoding 296 amino acids. In addition, real-time RT-PCR analysis showed that gKLF7 was broadly expressed in all 15 chicken tissues selected, and its expression was significantly different in spleen, proventriculus, abdominal fat, brain, leg muscle, gizzard and heart between fat and lean broilers at 7 weeks of age. Additionally, one novel single nucleotide polymorphism (SNP), XM_426569.3: c. A141G, was identified in the second exon of gKLF7. Association analysis showed that this locus was significantly associated with fatness traits in Arbor Acres broiler random population and the eighth generation of Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF) population (P < 0.05). These results suggest that gKLF7 might be a candidate gene for chicken fatness traits.
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Affiliation(s)
- Zhi-Wei Zhang
- Key Laboratory of Chicken Genetics and Breeding, Ministry of Agriculture, Harbin 150030, China
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27
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Kruppel-like factor 7 overexpression suppresses hematopoietic stem and progenitor cell function. Blood 2012; 120:2981-9. [PMID: 22936656 DOI: 10.1182/blood-2012-02-409839] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Increased expression of Kruppel-like factor 7 (KLF7) is an independent predictor of poor outcome in pediatric acute lymphoblastic leukemia. The contribution of KLF7 to hematopoiesis has not been previously described. Herein, we characterized the effect on murine hematopoiesis of the loss of KLF7 and enforced expression of KLF7. Long-term multilineage engraftment of Klf7(-/-) cells was comparable with control cells, and self-renewal, as assessed by serial transplantation, was not affected. Enforced expression of KLF7 results in a marked suppression of myeloid progenitor cell growth and a loss of short- and long-term repopulating activity. Interestingly, enforced expression of KLF7, although resulting in multilineage growth suppression that extended to hematopoietic stem cells and common lymphoid progenitors, spared T cells and enhanced the survival of early thymocytes. RNA expression profiling of KLF7-overexpressing hematopoietic progenitors identified several potential target genes mediating these effects. Notably, the known KLF7 target Cdkn1a (p21(Cip1/Waf1)) was not induced by KLF7, and loss of CDKN1A does not rescue the repopulating defect. These results suggest that KLF7 is not required for normal hematopoietic stem and progenitor function, but increased expression, as seen in a subset of lymphoid leukemia, inhibits myeloid cell proliferation and promotes early thymocyte survival.
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28
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Abstract
EHD {EH [Eps15 (epidermal growth factor receptor substrate 15) homology]-domain-containing} proteins participate in several endocytic events, such as the internalization and the recycling processes. There are four EHD proteins in mammalian cells, EHD1–EHD4, each with diverse roles in the recycling pathway of endocytosis. EHD2 is a plasma-membrane-associated member of the EHD family that regulates internalization. Since several endocytic proteins have been shown to undergo nucleocytoplasmic shuttling and have been assigned roles in regulation of gene expression, we tested the possibility that EHD proteins also shuttle to the nucleus. Our results showed that, among the three EHD proteins (EHD1–EHD3) that were tested, only EHD2 accumulates in the nucleus under nuclear export inhibition treatment. Moreover, the presence of a NLS (nuclear localization signal) was essential for its entry into the nucleus. Nuclear exit of EHD2 depended partially on its NES (nuclear export signal). Elimination of a potential SUMOylation site in EHD2 resulted in a major accumulation of the protein in the nucleus, indicating the involvement of SUMOylation in the nuclear exit of EHD2. We confirmed the SUMOylation of EHD2 by employing co-immunoprecipitation and the yeast two-hybrid system. Using GAL4-based transactivation assay as well as a KLF7 (Krüppel-like factor 7)-dependent transcription assay of the p21WAF1/Cip1 [CDKN1A (cyclin-dependent kinase inhibitor 1A)] gene, we showed that EHD2 represses transcription. qRT-PCR (quantitative real-time PCR) of RNA from cells overexpressing EHD2 or of RNA from cells knocked down for EHD2 confirmed that EHD2 represses transcription of the p21WAF1/Cip1 gene.
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29
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Krüppel-like Factor 7 engineered for transcriptional activation promotes axon regeneration in the adult corticospinal tract. Proc Natl Acad Sci U S A 2012; 109:7517-22. [PMID: 22529377 DOI: 10.1073/pnas.1120684109] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Axon regeneration in the central nervous system normally fails, in part because of a developmental decline in the intrinsic ability of CNS projection neurons to extend axons. Members of the KLF family of transcription factors regulate regenerative potential in developing CNS neurons. Expression of one family member, KLF7, is down-regulated developmentally, and overexpression of KLF7 in cortical neurons in vitro promotes axonal growth. To circumvent difficulties in achieving high neuronal expression of exogenous KLF7, we created a chimera with the VP16 transactivation domain, which displayed enhanced neuronal expression compared with the native protein while maintaining transcriptional activation and growth promotion in vitro. Overexpression of VP16-KLF7 overcame the developmental loss of regenerative ability in cortical slice cultures. Adult corticospinal tract (CST) neurons failed to up-regulate KLF7 in response to axon injury, and overexpression of VP16-KLF7 in vivo promoted both sprouting and regenerative axon growth in the CST of adult mice. These findings identify a unique means of promoting CST axon regeneration in vivo by reengineering a developmentally down-regulated, growth-promoting transcription factor.
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30
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Ma L, Qu Y, Huai Y, Li Z, Wang J, Lan X, Zhang C, Wang J, Chen H. Polymorphisms identification and associations of KLF7 gene with cattle growth traits. Livest Sci 2011. [DOI: 10.1016/j.livsci.2010.04.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Hughes AL, Buitenhuis AJ. Reduced variance of gene expression at numerous loci in a population of chickens selected for high feather pecking. Poult Sci 2010; 89:1858-69. [PMID: 20709970 DOI: 10.3382/ps.2010-00827] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Changes in gene expression in response to selection were studied by comparing microarray expression profiles among a population of domestic chickens selected for high feather pecking (FP) with a control population and a population selected for low FP. No transcripts showed significant differences among populations with respect to mean expression scores, but numerous transcripts showed reduced variance in expression scores in the high FP population in comparison to control and low FP populations. The reduction in variance in the high FP population generally involved transcripts whose expression scores had a negatively skewed distribution in the control population but not in the high FP population. A certain number of these transcripts corresponded to genes whose expression was significantly associated with either severe FP (SFP) or gentle FP. The patterns of gene expression associated with SFP and gentle FP were distinct, suggesting that very distinct underlying neural mechanisms underlie these 2 behaviors, with SFP showing more signs of an association with synaptic plasticity and with an immunosuppressive stress response.
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Affiliation(s)
- A L Hughes
- Department of Biological Sciences, University of South Carolina, Columbia 29208, USA.
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32
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Abstract
Krüppel-like factors (KLFs), members of the zinc-finger family of transcription factors capable of binding GC-rich sequences, have emerged as critical regulators of important functions all over the body. They are characterised by a highly conserved C-terminal DNA-binding motif containing three C2H2 zinc-finger domains, with variable N-terminal regulatory domains. Currently, there are 17 KLFs annotated in the human genome. In spite of their structural similarity to one another, the genes encoding different KLFs are scattered all over the genome. By virtue of their ability to activate and/or repress the expression of a large number of genes, KLFs regulate a diverse array of developmental events and cellular processes, such as erythropoiesis, cardiac remodelling, adipogenesis, maintenance of stem cells, epithelial barrier formation, control of cell proliferation and neoplasia, flow-mediated endothelial gene expression, skeletal and smooth muscle development, gluconeogenesis, monocyte activation, intestinal and conjunctival goblet cell development, retinal neuronal regeneration and neonatal lung development. Characteristic features, nomenclature, evolution and functional diversities of the human KLFs are reviewed here.
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Affiliation(s)
- Shivalingappa K Swamynathan
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Eye and Ear Institute, Room 1025, Pittsburgh, PA 15213, USA.
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33
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Askew EB, Bai S, Hnat AT, Minges JT, Wilson EM. Melanoma antigen gene protein-A11 (MAGE-11) F-box links the androgen receptor NH2-terminal transactivation domain to p160 coactivators. J Biol Chem 2009; 284:34793-808. [PMID: 19828458 DOI: 10.1074/jbc.m109.065979] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Androgen-dependent transcriptional activity by the androgen receptor (AR) and its coregulators is required for male reproductive development and function. In humans and other primates, melanoma antigen gene protein-A11 (MAGE-11) is an AR selective coregulator that increases AR transcriptional activity. Here we show that the interaction between AR and MAGE-11 is mediated by AR NH(2)-terminal FXXLF motif binding to a highly conserved MAGE-11 F-box in the MAGE homology domain, and is modulated by serum stimulation of mitogen-activated protein kinase phosphorylation of MAGE-11 Ser-174. The MAGE-11-dependent increase in AR transcriptional activity is mediated by a direct interaction between MAGE-11 and transcriptional intermediary factor 2 (TIF2) through the NH(2)-terminal region of TIF2, and by a MAGE-11 FXXIF motif interaction with an F-box-like region in activation domain 1 of TIF2. The results suggest that MAGE-11 functions as a bridging factor to recruit AR coactivators through a novel FXX(L/I)F motif-F-box interaction paradigm.
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Affiliation(s)
- Emily B Askew
- Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599-7500, USA
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34
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Raible DW, Ungos JM. Specification of sensory neuron cell fate from the neural crest. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 589:170-80. [PMID: 17076281 DOI: 10.1007/978-0-387-46954-6_10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
How distinct cell fates are generated from initially homogeneous cell populations is a driving question in developmental biology. The neural crest is one such cell population that is capable of producing an incredible array of derivatives. Cells as different in function and form as the pigment cells in the skin or the neurons and glia of the peripheral nervous system are all derived from neural crest. How do these cells choose to migrate along distinct routes, populate defined regions of the embryo and differentiate into specific cell types? This chapter focuses on the development of one particular neural crest derivative, sensory neurons, as a model for studying these questions of cell fate specification. In the head, sensory neurons reside in the trigeminal and epibranchial ganglia, while in the trunk they form the spinal or dorsal root ganglia (DRG). The development of the DRG will be the main focus of this review. The neurons and glia of the DRG derive from trunk neural crest cells that coalesce at the lateral edge of the spinal cord (Fig. 1). These neural crest cells migrate along the same routes as neural crest cells that populate the autonomic sympathetic ganglia located along the dorsal aorta. Somehow DRG precursors must make the decision to stop and adopt a sensory fate adjacent to the spinal cord rather than continuing on to become part of the autonomic ganglia. Moreover, once the DRG precursors aggregate in their final positions there are still a number of fate choices to be made. The mature DRG is composed of many neurons with different morphologies and distinct biochemical properties as well as glial cells that support these neurons.
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Affiliation(s)
- David W Raible
- Department of Biological Structure, University of Washington, Seattle, Washington, USA.
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35
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Abstract
Regulation of protein stability through the ubiquitin proteasome system is a key mechanism underlying numerous cellular processes. The ubiquitin protein ligases (or E3) are in charge of substrate specificity and therefore play a pivotal role in the pathway. Among the several different E3 enzyme families, the SCF (Skp1-Cullin-F box protein) is one of the largest and best characterized. F-box proteins, in addition to the loosely conserved F-box motif that binds Skp1, often carry typical protein interaction domains and are proposed to recruit the substrate to the SCF complex. Strikingly, genomes analysis revealed the presence of large numbers of F-box proteins topping to nearly 700 predicted in Arabidopsis thaliana. Recent evidences in various species suggest that some F-box proteins have functions not directly related to the SCF complex raising questions about the actual connection between the large F-box protein family and protein degradation, but also about their origins and evolution.
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Affiliation(s)
- Damien Hermand
- Laboratoire de Génétique Moléculaire (GEMO), Facultés Universitaires Notre-Dame de la Paix, Rue de Bruxelles 61, 5000 Namur, Belgium
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Kajimura D, Dragomir C, Ramirez F, Laub F. Identification of genes regulated by transcription factor KLF7 in differentiating olfactory sensory neurons. Gene 2006; 388:34-42. [PMID: 17123745 DOI: 10.1016/j.gene.2006.09.027] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 08/10/2006] [Accepted: 09/23/2006] [Indexed: 10/24/2022]
Abstract
Gene targeting in mice has recently demonstrated that transcription factor KLF7 plays a critical role in neurite outgrowth and neuronal survival. Here we extended this genetic evidence by establishing the transcriptional profile of differentiating olfactory sensory neurons (OSNs) in Klf7(-/-) mice, and by identifying relevant genes that are directly regulated by KLF7. Functional clustering of DNA microarray data revealed that loss of KLF7 affects primarily the activity of genes involved in OSN differentiation, axonal growth, cytoskeletal dynamics, cell adhesion and synaptogenesis. Cell transfection experiments, on the other hand, demonstrated that the promoters of the genes encoding the OSN-specific OMP and the adhesion molecule L1 are both activated by KLF7 binding to CACCC motifs. Collectively, these results advance knowledge of transcriptional regulation of olfactory neurogenesis and KLF7 action.
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Affiliation(s)
- Daisuke Kajimura
- Child Health Institute of New Jersey, UMDNJ-Robert Wood Johnson Medical School, 89 French Street, New Brunswick, NJ 08901, United States
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Smaldone S, Ramirez F. Multiple pathways regulate intracellular shuttling of MoKA, a co-activator of transcription factor KLF7. Nucleic Acids Res 2006; 34:5060-8. [PMID: 16990251 PMCID: PMC1636432 DOI: 10.1093/nar/gkl659] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/15/2006] [Accepted: 08/28/2006] [Indexed: 12/21/2022] Open
Abstract
MoKA is a novel F-box containing protein that interacts with and stimulates the activity of transcription factor KLF7, a regulator of neuronal differentiation. MoKA accumulates throughout the cell and predominantly in the cytosol, consistent with the presence of several putative nuclear localization and export signals (NLSs and NESs). The present study was designed to refine the identity and location of the sequences responsible for MoKA intracellular shuttling and transcriptional activity. Forced expression of fusion proteins in mammalian cells demonstrated that only one of three putative NLSs potentially recognized by karyopherin receptors is involved in nuclear localization of MoKA. By contrast, three distinct sequences were found to participate in mediating cytoplasmic accumulation. One of them is structurally and functionally related to the leucine-rich export signal that interacts with the exportin 1 (CRM1) receptor. The other two export signals instead display either a novel leucine-rich sequence or an undefined peptide motif, and both appear to act through CRM1-independent pathways. Finally, transcriptional analyses using the chimeric GAL4 system mapped the major activation domain of MoKA to a highly acidic sequence that resides between the NLS and NES clusters.
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Affiliation(s)
- Silvia Smaldone
- Child Health Institute of New Jersey, Robert W. Johnson Medical School89 French Street, New Brunswick, NJ 08901, USA
- CEINGE Biotecnologie Avanzate80131 Naples, Italy
| | - Francesco Ramirez
- To whom correspondence should be addressed. Tel: +1 732 235 9534; Fax: +1 732 235 9333;
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38
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Antoniv TT, Tanaka S, Sudan B, De Val S, Liu K, Wang L, Wells DJ, Bou-Gharios G, Ramirez F. Identification of a repressor in the first intron of the human alpha2(I) collagen gene (COL1A2). J Biol Chem 2005; 280:35417-23. [PMID: 16091368 DOI: 10.1074/jbc.m502681200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The human and mouse genes that code for the alpha2 chain of collagen I (COL1A2 and Col1a2, respectively) share a common chromatin structure and nearly identical proximal promoter and far upstream enhancer sequences. Despite these homologies, species-specific differences have been reported regarding the function of individual cis-acting elements, such as the first intron sequence. In the present study, we have investigated the transcriptional contribution of the unique open chromatin site in the first intron of COL1A2 using a transgenic mouse model. DNase I footprinting identified a cluster of three distinct areas of nuclease protection (FI1-3) that span from nucleotides +647 to +760, relative to the transcription start site, and which contain consensus sequences for GATA and interferon regulatory factor (IRF) transcription factors. Gel mobility shift and chromatin immunoprecipitation assays corroborated this last finding by documenting binding of GATA-4 and IRF-1 and IRF-2 to the first intron sequence. Moreover, a short sequence encompassing the three footprints was found to inhibit expression of transgenic constructs containing the COL1A2 proximal promoter and far upstream enhancer in a position-independent manner. Mutations inserted into each of the footprints restored transgenic expression to different extents. These results therefore indicated that the unique open chromatin site of COL1A2 corresponds to a repressor, the activity of which seems to be mediated by the concerted action of GATA and IRF proteins. More generally, the study reiterated the existence of species-specific difference in the regulatory networks of the mammalian alpha2(I) collagen coding genes.
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Affiliation(s)
- Taras T Antoniv
- Laboratory of Genetics and Organogenesis, Research Division of the Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York 10021, USA
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39
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Laub F, Lei L, Sumiyoshi H, Kajimura D, Dragomir C, Smaldone S, Puche AC, Petros TJ, Mason C, Parada LF, Ramirez F. Transcription factor KLF7 is important for neuronal morphogenesis in selected regions of the nervous system. Mol Cell Biol 2005; 25:5699-711. [PMID: 15964824 PMCID: PMC1157008 DOI: 10.1128/mcb.25.13.5699-5711.2005] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Krüppel-like transcription factors (KLFs) are important regulators of cell proliferation and differentiation in several different organ systems. The mouse Klf7 gene is strongly active in postmitotic neuroblasts of the developing nervous system, and the corresponding protein stimulates transcription of the cyclin-dependent kinase inhibitor p21waf/cip gene. Here we report that loss of KLF7 activity in mice leads to neonatal lethality and a complex phenotype which is associated with deficits in neurite outgrowth and axonal misprojection at selected anatomical locations of the nervous system. Affected axon pathways include those of the olfactory and visual systems, the cerebral cortex, and the hippocampus. In situ hybridizations and immunoblots correlated loss of KLF7 activity in the olfactory epithelium with significant downregulation of the p21waf/cip and p27kip1 genes. Cotransfection experiments extended the last finding by documenting KLF7's ability to transactivate a reporter gene construct driven by the proximal promoter of p27kip1. Consistent with emerging evidence for a role of Cip/Kip proteins in cytoskeletal dynamics, we also documented p21waf/cip and p27kip1 accumulation in the cytoplasm of differentiating olfactory sensory neurons. KLF7 activity might therefore control neuronal morphogenesis in part by optimizing the levels of molecules that promote axon outgrowth.
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Affiliation(s)
- Friedrich Laub
- Laboratory of Genetics and Organogenesis, Research Division of the Hospital for Special Surgery, and Department of Physiology and Biophysics at Weill Medical College of Cornell University, 535 East 70th St., New York, New York 10021, USA
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