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Rehman MSU, Mushtaq M, Hassan FU, Zia-ur Rehman, Mushahid M, Shokrollahi B. Comparative Genomic Characterization of Insulin-Like Growth Factor Binding Proteins in Cattle and Buffalo. BIOMED RESEARCH INTERNATIONAL 2022; 2022:5893825. [PMID: 35924270 PMCID: PMC9343199 DOI: 10.1155/2022/5893825] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/30/2022] [Accepted: 07/06/2022] [Indexed: 11/30/2022]
Abstract
The somatotropic axis consists of genes associated with economic traits like muscle growth and carcass traits in livestock. Insulin-like growth factor binding proteins (IGFBPs) are the major proteins that play a vital role in the somatotropic axis. The present study performed a genome-wide characterization of IGFBP genes in cattle. Genomic sequences of the IGFBP gene family for different mammals (cattle, buffalo, goat, and sheep) were recovered from the NCBI database. Sequence analyses were performed to investigate cattle's genomic variations in the IGFBP gene family. Phylogenetic analysis, gene structure, motif patterns, and conserved domain analysis (CDA) of the IGFBP family revealed the evolutionarily conserved nature of the IGFBP genes in cattle and other studied species. Physicochemical properties of IGFBP proteins in cattle revealed that most of these proteins are unstable, hydrophilic, thermostable, and acidic. Comparative amino acid analysis revealed variations in all protein sequences with single indels in IGFBP3 and IGFBP6. Mutation analysis revealed only one nonsynonymous mutation D212 > E in the IGFBP6 protein of cattle. A total of 245 nuclear hormone receptor (NHRs) sites were detected, including 139 direct repeats (DR), 65 everted repeats (ER), and 41 inverted repeats (IR). Out of 133 transcription factors (TFs), 10 TFs (AHR, AHRARNT, AP4, CMYB, E47, EGR2, GATA, SP1, and SRF) had differential distribution (P value < 0.05) of putative transcriptional binding sites (TFBS) in cattle compared to buffalo. Synteny analysis revealed the conserved nature of genes between cattle and buffalo. Two gene pairs (IGFBP1/IGFBP3 and IGFBP2/IGFBP5) showed tandem duplication events in cattle and buffalo. This study highlights the functional importance of genomic variation in IGFBP genes and necessitates further investigations better to understand the role and mechanisms of IGFBPs in bovines.
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Affiliation(s)
- Muhammad Saif-ur Rehman
- Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad 38040, Pakistan
| | - Muqeet Mushtaq
- Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad 38040, Pakistan
| | - Faiz-ul Hassan
- Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad 38040, Pakistan
| | - Zia-ur Rehman
- University of Agriculture, Faisalabad–Subcampus Toba Tek Singh, Pakistan
| | - Muhammad Mushahid
- Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad 38040, Pakistan
| | - Borhan Shokrollahi
- Department of Animal Science, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran
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Transcription Factor AP4 Mediates Cell Fate Decisions: To Divide, Age, or Die. Cancers (Basel) 2021; 13:cancers13040676. [PMID: 33567514 PMCID: PMC7914591 DOI: 10.3390/cancers13040676] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 01/31/2021] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Here, we review the literature on Activating Enhancer-Binding Protein 4 (AP4)/transcription factor AP4 (TFAP4) function and regulation and its role in cancer. Elevated expression of AP4 was detected in tumors of various organs and is associated with poor patient survival. AP4 is encoded by a Myc target gene and mediates cell fate decisions by regulating multiple processes, such as cell proliferation, epithelial-mesenchymal transition, stemness, apoptosis, and cellular senescence. Thereby, AP4 may be critical for tumor initiation and progression. In this review article, we summarize published evidence showing how AP4 functions as a transcriptional activator and repressor of a plethora of direct target genes in various physiological and pathological conditions. We also highlight the complex interactions of AP4 with c-Myc, N-Myc, p53, lncRNAs, and miRNAs in feed-back loops, which control AP4 levels and mediate AP4 functions. In the future, a better understanding of AP4 may contribute to improved prognosis and therapy of cancer. Abstract Activating Enhancer-Binding Protein 4 (AP4)/transcription factor AP4 (TFAP4) is a basic-helix-loop-helix-leucine-zipper transcription factor that was first identified as a protein bound to SV40 promoters more than 30 years ago. Almost 15 years later, AP4 was characterized as a target of the c-Myc transcription factor, which is the product of a prototypic oncogene that is activated in the majority of tumors. Interestingly, AP4 seems to represent a central hub downstream of c-Myc and N-Myc that mediates some of their functions, such as proliferation and epithelial-mesenchymal transition (EMT). Elevated AP4 expression is associated with progression of cancer and poor patient prognosis in multiple tumor types. Deletion of AP4 in mice points to roles of AP4 in the control of stemness, tumor initiation and adaptive immunity. Interestingly, ex vivo AP4 inactivation results in increased DNA damage, senescence, and apoptosis, which may be caused by defective cell cycle progression. Here, we will summarize the roles of AP4 as a transcriptional repressor and activator of target genes and the contribution of protein and non-coding RNAs encoded by these genes, in regulating the above mentioned processes. In addition, proteins interacting with or regulating AP4 and the cellular signaling pathways altered after AP4 dysregulation in tumor cells will be discussed.
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Boughanem H, Yubero-Serrano EM, López-Miranda J, Tinahones FJ, Macias-Gonzalez M. Potential Role of Insulin Growth-Factor-Binding Protein 2 as Therapeutic Target for Obesity-Related Insulin Resistance. Int J Mol Sci 2021; 22:ijms22031133. [PMID: 33498859 PMCID: PMC7865532 DOI: 10.3390/ijms22031133] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/13/2021] [Accepted: 01/21/2021] [Indexed: 12/26/2022] Open
Abstract
Evidence from observational and in vitro studies suggests that insulin growth-factor-binding protein type 2 (IGFBP2) is a promising protein in non-communicable diseases, such as obesity, insulin resistance, metabolic syndrome, or type 2 diabetes. Accordingly, great efforts have been carried out to explore the role of IGFBP2 in obesity state and insulin-related diseases, which it is typically found decreased. However, the physiological pathways have not been explored yet, and the relevance of IGFBP2 as an important pathway integrator of metabolic disorders is still unknown. Here, we review and discuss the molecular structure of IGFBP2 as the first element of regulating the expression of IGFBP2. We highlight an update of the association between low serum IGFBP2 and an increased risk of obesity, type 2 diabetes, metabolic syndrome, and low insulin sensitivity. We hypothesize mechanisms of IGFBP2 on the development of obesity and insulin resistance in an insulin-independent manner, which meant that could be evaluated as a therapeutic target. Finally, we cover the most interesting lifestyle modifications that regulate IGFBP2, since lifestyle factors (diet and/or physical activity) are associated with important variations in serum IGFBP2.
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Affiliation(s)
- Hatim Boughanem
- Department of Endocrinology and Nutrition, Institute of Biomedical Research Institute in Malaga (IBIMA), Virgen de la Victoria University Hospital, 29010 Málaga, Spain;
| | - Elena M. Yubero-Serrano
- Lipids and Atherosclerosis Unit, Maimonides Institute for Biomedical Research in Cordoba (IMIBIC), Reina Sofia University Hospital, University of Córdoba, 14004 Córdoba, Spain; (E.M.Y.-S.); (J.L.-M.)
- CIBEROBN (CIBER in Physiopathology of Obesity and Nutrition), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - José López-Miranda
- Lipids and Atherosclerosis Unit, Maimonides Institute for Biomedical Research in Cordoba (IMIBIC), Reina Sofia University Hospital, University of Córdoba, 14004 Córdoba, Spain; (E.M.Y.-S.); (J.L.-M.)
- CIBEROBN (CIBER in Physiopathology of Obesity and Nutrition), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Francisco J. Tinahones
- Department of Endocrinology and Nutrition, Institute of Biomedical Research Institute in Malaga (IBIMA), Virgen de la Victoria University Hospital, 29010 Málaga, Spain;
- CIBEROBN (CIBER in Physiopathology of Obesity and Nutrition), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (F.J.T.); (M.M.-G.); Tel.: +34-951-036-2647 (F.J.T. & M.M.-G.); Fax: +34-951-924-651 (F.J.T. & M.M.-G.)
| | - Manuel Macias-Gonzalez
- Department of Endocrinology and Nutrition, Institute of Biomedical Research Institute in Malaga (IBIMA), Virgen de la Victoria University Hospital, 29010 Málaga, Spain;
- CIBEROBN (CIBER in Physiopathology of Obesity and Nutrition), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (F.J.T.); (M.M.-G.); Tel.: +34-951-036-2647 (F.J.T. & M.M.-G.); Fax: +34-951-924-651 (F.J.T. & M.M.-G.)
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Differential cellular responses by oncogenic levels of c-Myc expression in long-term confluent retinal pigment epithelial cells. Mol Cell Biochem 2017; 443:193-204. [PMID: 29188535 DOI: 10.1007/s11010-017-3224-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/23/2017] [Indexed: 01/10/2023]
Abstract
c-Myc is a highly pleiotropic transcription factor known to control cell cycle progression, apoptosis, and cellular transformation. Normally, ectopic expression of c-Myc is associated with promoting cell proliferation or triggering cell death via activating p53. However, it is not clear how the levels of c-Myc lead to different cellular responses. Here, we generated a series of stable RPE cell clones expressing c-Myc at different levels, and found that consistent low level of c-Myc induced cellular senescence by activating AP4 in post-confluent RPE cells, while the cells underwent cell death at high level of c-Myc. In addition, high level of c-Myc could override the effect of AP4 on cellular senescence. Further knockdown of AP4 abrogated senescence-like phenotype in cells expressing low level of c-Myc, and accelerated cell death in cells with medium level of c-Myc, indicating that AP4 was required for cellular senescence induced by low level of c-Myc.
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Lawlor N, Youn A, Kursawe R, Ucar D, Stitzel ML. Alpha TC1 and Beta-TC-6 genomic profiling uncovers both shared and distinct transcriptional regulatory features with their primary islet counterparts. Sci Rep 2017; 7:11959. [PMID: 28931935 PMCID: PMC5607285 DOI: 10.1038/s41598-017-12335-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/06/2017] [Indexed: 01/09/2023] Open
Abstract
Alpha TC1 (αTC1) and Beta-TC-6 (βTC6) mouse islet cell lines are cellular models of islet (dys)function and type 2 diabetes (T2D). However, genomic characteristics of these cells, and their similarities to primary islet alpha and beta cells, are undefined. Here, we report the epigenomic (ATAC-seq) and transcriptomic (RNA-seq) landscapes of αTC1 and βTC6 cells. Each cell type exhibits hallmarks of its primary islet cell counterpart including cell-specific expression of beta (e.g., Pdx1) and alpha (e.g., Arx) cell transcription factors (TFs), and enrichment of binding motifs for these TFs in αTC1/βTC6 cis-regulatory elements. αTC1/βTC6 transcriptomes overlap significantly with the transcriptomes of primary mouse/human alpha and beta cells. Our data further indicate that ATAC-seq detects cell-specific regulatory elements for cell types comprising ≥ 20% of a mixed cell population. We identified αTC1/βTC6 cis-regulatory elements orthologous to those containing type 2 diabetes (T2D)-associated SNPs in human islets for 33 loci, suggesting these cells’ utility to dissect T2D molecular genetics in these regions. Together, these maps provide important insights into the conserved regulatory architecture between αTC1/βTC6 and primary islet cells that can be leveraged in functional (epi)genomic approaches to dissect the genetic and molecular factors controlling islet cell identity and function.
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Affiliation(s)
- Nathan Lawlor
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Ahrim Youn
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Romy Kursawe
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Duygu Ucar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, 06032, USA. .,Department of Genetics & Genome Sciences, University of Connecticut, Farmington, CT, 06032, USA.
| | - Michael L Stitzel
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, 06032, USA. .,Department of Genetics & Genome Sciences, University of Connecticut, Farmington, CT, 06032, USA.
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6
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Wang Y, Wong MMK, Zhang X, Chiu SK. Ectopic AP4 expression induces cellular senescence via activation of p53 in long-term confluent retinal pigment epithelial cells. Exp Cell Res 2015; 339:135-46. [PMID: 26439195 DOI: 10.1016/j.yexcr.2015.09.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 09/16/2015] [Accepted: 09/19/2015] [Indexed: 01/09/2023]
Abstract
When cells are grown to confluence, cell-cell contact inhibition occurs and drives the cells to enter reversible quiescence rather than senescence. Confluent retinal pigment epithelial (RPE) cells exhibiting contact inhibition was used as a model in this study to examine the role of overexpression of transcription factor AP4, a highly expressed transcription factor in many types of cancer, in these cells during long-term culture. We generated stable inducible RPE cell clones expressing AP4 or AP4 without the DNA binding domain (DN-AP4) and observed that, when cultured for 24 days, RPE cells with a high level of AP4 exhibit a large, flattened morphology and even cease proliferating; these changes were not observed in DN-AP4-expressing cells or non-induced cells. In addition, AP4-expressing cells exhibited senescence-associated β-galactosidase activity and the senescence-associated secretory phenotype. We demonstrated that the induced cellular senescence was mediated by enhanced p53 expression and that AP4 regulates the p53 gene by binding directly to two of the three E-boxes present on the promoter of the p53 gene. Moreover, we showed that serum is essential for AP4 in inducing p53-associated cellular senescence. Collectively, we showed that overexpression of AP4 mediates cellular senescence involving in activation of p53 in long-term post-confluent RPE cells.
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Affiliation(s)
- Yiping Wang
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Matthew Man-Kin Wong
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Xiaojian Zhang
- Institute of Bioengineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, China
| | - Sung-Kay Chiu
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
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Hoeflich A, Russo VC. Physiology and pathophysiology of IGFBP-1 and IGFBP-2 - consensus and dissent on metabolic control and malignant potential. Best Pract Res Clin Endocrinol Metab 2015; 29:685-700. [PMID: 26522454 DOI: 10.1016/j.beem.2015.07.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
IGFBP-1 and IGFBP-2 are suppressed by growth hormone and therefore represent less prominent members of the IGFBP family when compared to IGFBP-3 that carries most of the IGFs during circulation under normal conditions in humans in vivo. As soon as the GH signal is decreased expression of IGF-I and IGFBP-3 is reduced. Under conditions of lowered suppression by GH the time seems come for IGFBP-1 and IGFBP-2. Both IGFBPs are potent effectors of growth and metabolism. Secretion of IGFBP-1 and IGFBP-2 is further suppressed by insulin and diminished with increasing obesity. Both IGFBP family members share the RGD sequence motif that mediates binding to integrins and is linked to PTEN/PI3K signalling. In mice, IGFBP-2 prevents age- and diet-dependent glucose insensitivity and blocks differentiation of preadipocytes. The latter function is modulated by two distinct heparin-binding domains of IGFBP-2 which are lacking in IGFBP-1. IGFBP-2 is further regulated by leptin and has been demonstrated to affect insulin sensitivity and glucose tolerance, further supporting a particular role of IGFBP-2 in glucose and fat metabolism. Since IGFBP-2 is controlled by sex steroids as well, we devised a scheme to compare IGFBP effects in breast, ovarian and prostate cancer. While a positive association does not seem to exist with IGFBP-1 and risk of cancers within these reproductive tissues, a relationship between IGFBP-2 and breast cancer, ovarian cancer and prostate cancer does indeed appear to be present. To date, the specific roles of IGFBP-2 in estrogen signalling are unclear, though there is accumulating evidence for an effect of IGFBP-2 on PI3K signalling via PTEN, particularly in breast cancer.
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Affiliation(s)
- Andreas Hoeflich
- Institute for Genome Biology, Leibniz-Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
| | - Vincenzo C Russo
- Hormone Research, Murdoch Childrens Research Institute, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia.
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Chen S, Chiu SK. AP4 activates cell migration and EMT mediated by p53 in MDA-MB-231 breast carcinoma cells. Mol Cell Biochem 2015; 407:57-68. [PMID: 26037074 DOI: 10.1007/s11010-015-2454-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 05/16/2015] [Indexed: 11/25/2022]
Abstract
Tumor metastasis is the primary cause of mortality in most cancer patients. Before disassociation from the tumors, most of malignant tumor cells undergo the epithelial-mesenchymal transition to break away from the adhesions between the cells and the surrounding extracellular matrix. Recently, activating enhancer-binding protein (AP4) has been shown to be a mediator of EMT in colorectal cancer and high level of AP4 correlates with poor prognosis in cancer patients. It has been found that AP4 upregulates the genes involved in EMT and cell proliferation in colorectal cancer cells and that the aggressive human breast cancer cells MDA-MB-231 are highly metastatic. Therefore, we tested the hypothesis that AP4 may also affect cell migration and EMT in this cell type. Three different assays, including the wound-healing assay, the Boyden chamber assay, and the cell tracking assay, were employed to confirm that AP4 activated both cell migration and invasion. Immunofluorescence staining and Western blot analysis revealed that the cells underwent EMT when AP4 was upregulated. In contrast, overexpression of dominant-negative AP4, lacking the DNA-binding domain, inactivated the DNA-binding ability of endogenous AP4 and led to lower cell motility. Furthermore, we found that AP4 enhanced p53 expression at both transcriptional and translational levels. Knockdown of p53 by siRNA significantly diminished the activation of cell migration by AP4, indicating that AP4 can regulate cell migration via the activity of p53.
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Affiliation(s)
- Shaopeng Chen
- Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
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IGFBP-2: The dark horse in metabolism and cancer. Cytokine Growth Factor Rev 2015; 26:329-46. [DOI: 10.1016/j.cytogfr.2014.12.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/09/2014] [Indexed: 12/29/2022]
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Hoeflich A, Wirthgen E, David R, Classen CF, Spitschak M, Brenmoehl J. Control of IGFBP-2 Expression by Steroids and Peptide Hormones in Vertebrates. Front Endocrinol (Lausanne) 2014; 5:43. [PMID: 24778626 PMCID: PMC3985015 DOI: 10.3389/fendo.2014.00043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/20/2014] [Indexed: 12/03/2022] Open
Abstract
IGFBP-2 (1) has been described as a brain tumor oncogene (2) and is widely expressed in cancers from different origins (3-8). IGFBP-2 alone cannot cause malignant transformation, yet progression of brain tumors to higher grade (9) and also has been provided as a protective element in earlier stages of multistage colon carcinogenesis (10). Therefore, it is crucial to understand the factors that determine expression patterns of IGFBP-2 under normal and malignant conditions. The present review provides a comprehensive update of known factors that have an impact on expression of IGFBP-2.
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Affiliation(s)
- Andreas Hoeflich
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
- *Correspondence: Andreas Hoeflich, Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, Dummerstorf 18196, Germany e-mail:
| | | | - Robert David
- Reference and Translation Center for Cardiac Stem Cell Therapy, Rostock, Germany
| | | | - Marion Spitschak
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Julia Brenmoehl
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
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Bitra K, Palli SR. The members of bHLH transcription factor superfamily are required for female reproduction in the red flour beetle, Tribolium castaneum. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1481-9. [PMID: 20223247 PMCID: PMC2916060 DOI: 10.1016/j.jinsphys.2010.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/01/2010] [Accepted: 03/02/2010] [Indexed: 05/24/2023]
Abstract
Proteins containing the basic Helix-Loop-Helix (bHLH) domain function as transcription factors and play important roles during the development of various metazoans including insects, nematodes and vertebrates. Insect genomes contain more than 50 bHLH transcription factors, but the function of only a few of these proteins in regulation of female reproduction is known. Using RNA interference, we have tested knock-down in the expression of genes coding for bHLH transcription factors in newly emerged adult females to determine their function in regulation of female reproduction in the red flour beetle, Tribolium castaneum. Knock-down in the expression of genes coding for four bHLH transcription factors (TcSRC, TcSim1, TcAsh and TcDaughterless) caused mortality in the female beetles. In addition, knocking-down the expression of 16 bHLH genes affected oogenesis and knock-down in the expression of 13 genes affected embryogenesis. Two genes TcSide1 and TcSpineless are required for both oogenesis and embryogenesis. Thus, the data reported here showed that 31 bHLH transcription factors are required for female survival, reproduction and embryogenesis.
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Affiliation(s)
| | - Subba R. Palli
- Corresponding Author: Phone: 859 257 4962, Fax: 859 323 1120,
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Hu CH, Hong B, Xu WH. Identification of an E-box DNA binding protein, activated protein 4, and its function in regulating the expression of the gene encoding diapause hormone and pheromone biosynthesis-activating neuropeptide in Helicoverpa armigera. INSECT MOLECULAR BIOLOGY 2010; 19:243-252. [PMID: 20088871 DOI: 10.1111/j.1365-2583.2009.00983.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Activated protein 4 (AP-4), an E-box DNA-binding protein, was cloned from the cotton bollworm, Helicoverpa armigera (Har). The expression of Har-AP-4 mRNA and the protein that it encodes are significantly higher in nondiapause pupae than in diapause pupae. In vitro-translated Har-AP-4 can bind specifically to the E-box motif on the promoter of the diapause hormone and pheromone biosynthesis-activating neuropeptide (DH-PBAN). Har-AP-4, fused with the green fluorescent protein (GFP), is localized to the nucleus, and overexpression of Har-AP-4 can significantly activate the promoter of the DH-PBAN gene that is involved in nondiapause pupal development in H. armigera. These results suggest that Har-AP-4, which binds to the promoter of DH-PBAN, may play a role in regulating pupal development in H. armigera.
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Affiliation(s)
- C-H Hu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen (Zhongshan) University, Guangzhou, China
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Ku WC, Chiu SK, Chen YJ, Huang HH, Wu WG, Chen YJ. Complementary quantitative proteomics reveals that transcription factor AP-4 mediates E-box-dependent complex formation for transcriptional repression of HDM2. Mol Cell Proteomics 2009; 8:2034-50. [PMID: 19505873 PMCID: PMC2742435 DOI: 10.1074/mcp.m900013-mcp200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 05/26/2009] [Indexed: 01/13/2023] Open
Abstract
Transcription factor activating enhancer-binding protein 4 (AP-4) is a basic helix-loop-helix protein that binds to E-box elements. AP-4 has received increasing attention for its regulatory role in cell growth and development, including transcriptional repression of the human homolog of murine double minute 2 (HDM2), an important oncoprotein controlling cell growth and survival, by an unknown mechanism. Here we demonstrate that AP-4 binds to an E-box located in the HDM2-P2 promoter and represses HDM2 transcription in a p53-independent manner. Incremental truncations of AP-4 revealed that the C-terminal Gln/Pro-rich domain was essential for transcriptional repression of HDM2. To further delineate the molecular mechanism(s) of AP-4 transcriptional control and its potential implications, we used DNA-affinity purification followed by complementary quantitative proteomics, cICAT and iTRAQ labeling methods, to identify a previously unknown E-box-bound AP-4 protein complex containing 75 putative components. The two labeling methods complementarily quantified differentially AP-4-enriched proteins, including the most significant recruitment of DNA damage response proteins, followed by transcription factors, transcriptional repressors/corepressors, and histone-modifying proteins. Specific interaction of AP-4 with CCCTC binding factor, stimulatory protein 1, and histone deacetylase 1 (an AP-4 corepressor) was validated using AP-4 truncation mutants. Importantly, inclusion of trichostatin A did not alleviate AP-4-mediated repression of HDM2 transcription, suggesting a previously unidentified histone deacetylase-independent repression mechanism. In contrast, the complementary quantitative proteomics study suggested that transcription repression occurs via coordination of AP-4 with other transcription factors, histone methyltransferases, and/or a nucleosome remodeling SWI.SNF complex. In addition to previously known functions of AP-4, our data suggest that AP-4 participates in a transcriptional-regulating complex at the HDM2-P2 promoter in response to DNA damage.
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Affiliation(s)
- Wei-Chi Ku
- From the ‡Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
- §Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Sung-Kay Chiu
- ¶Department of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
| | - Yi-Ju Chen
- ‖Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Hsin-Hung Huang
- ‖Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Wen-Guey Wu
- From the ‡Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
- §Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yu-Ju Chen
- From the ‡Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan
- **Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, and
- ‡‡Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
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Hannenhalli SS, Middleton RP, Levy S, Perroud B, Holzwarth JA, McDonald K, Hannah SS. Identification and cross-species comparison of canine osteoarthritic gene regulatory cis-elements. Osteoarthritis Cartilage 2006; 14:830-8. [PMID: 16580849 DOI: 10.1016/j.joca.2006.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Accepted: 02/09/2006] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To better understand transcription regulation of osteoarthritis (OA) by examining common promoter motifs in canine osteoarthritic genes, to identify other genes containing these motifs and to assess the conservation of these motifs between canine, human, mouse and rat. DESIGN Differentially expressed transcripts in canine OA were mapped to the human genome. We thus identified 20 orthologous human transcripts representing 19 up-regulated genes and 62 orthologous transcripts representing 60 down-regulated genes. The 5 kbp upstream regions of these transcripts were used to identify binding sites and build promoter models based on those sites. The human genome was subsequently searched for other transcripts likely to be regulated by the same promoter models. Orthologous transcripts were then identified in canine, rat and mouse for determination of potential cross-species conservation of binding sites comprising the promoter model. RESULTS Four promoter models containing 5-6 transcripts and 5-8 common transcription factor binding sites were developed. They include binding sites for AP-4, AP-2alpha and gamma, and E2F. Several hundred other human genes were found to contain these promoter motifs. Furthermore these motifs were significantly over represented in the orthologous genes in canine, rat and mouse genomes. CONCLUSIONS We have developed and applied a computational methodology to identify common promoter elements implicated in OA and shared amongst four higher vertebrates. The transcription factors associated with these binding sites and other genes driven by these promoter motifs have been implicated in OA, chondrocyte development and with other biological factors involved in the disease.
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Affiliation(s)
- S S Hannenhalli
- Department of Genetics, University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Kwak I, Song S, Blum JL, Simmen RCM, Simmen FA. Enhancer- and silencer-like sequences that mediate insulin-like growth factor-binding protein-2 gene expression in uterine cells of pregnancy. DNA Cell Biol 2006; 25:6-18. [PMID: 16405396 DOI: 10.1089/dna.2006.25.6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The regulation of insulin-like growth factor-binding protein-2 (IGFBP-2) gene transcription in specific cell and developmental contexts is not well understood. Here, we identified DNA regions that mediate IGFBP-2 gene transcription in two of the three major cell types of the uterine endometrium of the early pregnant pig. Two clusters of transcriptional start sites at nucleotides -109/-105 and -96/-87 (+1, translational initiation site) in the porcine IGFBP-2 gene were localized in uterine endometrium and in primary cultures of endometrial glandular epithelial (GE) and stromal (ST) fibroblastic cells. Upstream regions of this gene (spanning -1,397/+73) were fused to a luciferase reporter gene, and the constructs were transiently transfected into endometrial GE and ST cells representative of pregnancy days 12 and 18 (day 115 = parturition). A short (110 bp) upstream region (-874/-765) stimulated the IGFBP-2 and heterologous SV40 promoters in the two cell types at both pregnancy days. Two noncontiguous copies of the novel sequence motif TCAGGG within the 110-bp fragment were implicated in transcriptional activity, since block mutation of these sequences led to a repression of SV40 basal promoter activity in endometrial cells. Southwestern blotting identified an endometrial nuclear protein of 34-kDa molecular weight that bound an oligonucleotide containing this motif, and EMSA suggested robust expression of this protein in early pregnancy endometrium and in ovary but at much reduced levels in endometrium at later pregnancy. A pair of E-box elements (CANNTG) within the 110 bp region was stimulatory to IGFBP-2 promoter activity; block mutation of these converted the 110-bp region into a potent transcriptional silencer in all but day 18 ST cells. Results identify novel DNA motifs that regulate the IGFBP-2 gene promoter in uterine endometrium in pregnancy-associated fashion.
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Affiliation(s)
- Inseok Kwak
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
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16
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Tsujimoto K, Ono T, Sato M, Nishida T, Oguma T, Tadakuma T. Regulation of the expression of caspase-9 by the transcription factor activator protein-4 in glucocorticoid-induced apoptosis. J Biol Chem 2005; 280:27638-44. [PMID: 15944155 DOI: 10.1074/jbc.m501304200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caspase-9 (Casp-9) induces death signals by triggering other types of caspase activation, and its expression greatly influences the onset of apoptosis. During the isolation of apoptosis-related genes involved in glucocorticoid (GC)-induced cell death in murine thymic lymphomas, we found that the antisense gene of the transcription factor activator protein-4 (AP-4) inhibited dexamethasone-induced apoptosis. Western blot analysis revealed that the expression of Bcl-xL, Bax, and Apaf-1 was not affected in cells transfected with sense or antisense AP-4 genes. In contrast, both the expression and activation of Casp-9 were inhibited in the antisense AP-4 transfectants. We isolated the 2.4-kb 5'-flanking region of Casp-9, and the promoter activity was investigated. We found the AP-4-binding sites at -1.55 and -1.38 kb to be responsible for the promoter activity. Furthermore, a negative cis-element was expected to exist between bases -1140 and -944. When the cells were treated with dexamethasone, a rapid down-regulation of AP-4 and Casp-9 was observed whether the cells were GC-sensitive lymphomas or GC-insensitive L929 fibroblast cells. In addition, L929 cells pretreated with dexamethasone were found to be resistant to subsequent treatment with etoposide, an apoptosis-inducing reagent. GC has a two-sided effect on apoptosis, i.e. a pro-apoptotic effect on certain cell types and a prosurvival effect on other cell types. Our findings will explain, at least in part, this effect.
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Affiliation(s)
- Kyoko Tsujimoto
- Department of Parasitology and Immunology, National Defense Medical College, 3-2 Namiki, Tokorozawa 359-8513, Japan
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17
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Cheng CK, Hoo RLC, Chow BKC, Leung PCK. Functional cooperation between multiple regulatory elements in the untranslated exon 1 stimulates the basal transcription of the human GnRH-II gene. Mol Endocrinol 2003; 17:1175-91. [PMID: 12663744 DOI: 10.1210/me.2002-0418] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The wide distribution of GnRH-II and conservation of its structure over all vertebrate classes suggest that the neuropeptide possesses vital biological functions. Although recent studies have shown that the expression of the human GnRH-II gene is regulated by cAMP and estrogen, the molecular mechanisms governing its basal transcription remain poorly understood. Using the neuronal TE-671 and placental JEG-3 cells, we showed that the minimal human GnRH-II promoter was located between nucleotide -1124 and -750 (relative to the translation start codon) and that the untranslated exon 1 was important to produce full promoter activity. Two putative E-box binding sites and one Ets-like element were identified within the first exon, and mutational analysis demonstrated that these cis-acting elements functioned cooperatively to stimulate the human GnRH-II gene transcription. EMSAs, UV cross-linking, and Southwestern blot analyses indicated that the basic helix-loop-helix transcription factor AP-4 bound specifically to the two E-box binding sites, whereas an unidentified protein bound to the Ets-like element. The functional importance of AP-4 in controlling human GnRH-II gene transcription was demonstrated by overexpression of sense and antisense full-length AP-4 cDNAs. Taken together, our present data demonstrate a novel mechanism in stimulating basal human GnRH-II gene transcription mediated by cooperative actions of multiple regulatory elements within the untranslated first exon of the gene.
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Affiliation(s)
- Chi Keung Cheng
- Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, Canada V6H 3V5
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18
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Simmen RCM, Zhang XL, Michel FJ, Min SH, Zhao G, Simmen FA. Molecular markers of endometrial epithelial cell mitogenesis mediated by the Sp/Krüppel-like factor BTEB1. DNA Cell Biol 2002; 21:115-28. [PMID: 11953011 DOI: 10.1089/104454902753604998] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Basic transcription element binding (BTEB1) protein is one of at least 20 Sp/KLF family members that function as transcriptional activators or repressors by binding to GC/GT-rich sequences within target genes to influence cellular homeostasis in mammals. Previously, we demonstrated that increased expression of BTEB1 in a human endometrial epithelial cell line Hec-1-A resulted in serum dependent-enhanced proliferation, which was accompanied by heightened expression of cell cycle- and growth-associated genes. In the present study, we examined the mechanism underlying the altered proliferative potential associated with BTEB1 by the identification of additional BTEB1 downstream gene targets and by the demonstration of BTEB1 transactivation of promoters for a number of growth-associated genes. Using mRNA differential display in the analysis of RNA populations from Hec-1-A sublines with high (4S, 9S) and low (2As, 3As) BTEB1 cellular content, we identified 10 distinct differentially expressed transcripts, nine of which had higher levels in S than in As sublines. The expression levels of two of these cDNAs, Axl receptor tyrosine kinase and mitosin, whose encoded products are implicated in cellular proliferation, were modestly induced by serum, albeit in a BTEB1-independent manner. Moreover, insulin-like growth factor-I, a mitogen present in serum, had no significant effect on their expression in either subline. In transient reporter assays, the basal activities of the Axl gene promoter and those for two other growth-regulatory genes, namely p21(WAF1) and IGFBP-2, were increased by serum and were significantly higher in 4S than in 2As lines. However, while BTEB1 and its ubiquitous family member Sp1 increased basal p21(WAF1) and IGFBP-2 transcription when added as expression constructs in the parental Hec-1-A cell line, only Sp1 activated Axl transcription, despite the presence in all three gene promoters of GC-enriched regions that presumably can bind BTEB1 and Sp1 with similar affinities. To elucidate intracellular signaling pathways that might involve BTEB1, inhibitors of specific kinase-dependent transducers were used in transient transfection assays involving the IGFBP-2 gene promoter in 4S and 2As sublines. While inhibitors of the MAPK, PI-3K, and PKA pathways elicited similar effects on the IGFBP-2 gene promoter activity, irrespective of cellular BTEB1 content, that for JNK had a more pronounced effect on Hec-1-A sublines exhibiting higher BTEB1 expression levels. Taken together, the results suggest that BTEB1 mediates the expression of growth-associated genes through direct and indirect transactivation mechanisms, one of which may involve the participation of a JNK family member.
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Affiliation(s)
- Rosalia C M Simmen
- Department of Animal Sciences and Interdisciplinary Concentration in Animal Molecular & Cell Biology, University of Florida, Gainesville, Florida 32611-0910, USA.
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Aranburu A, Carlsson R, Persson C, Leanderson T. Transcription factor AP-4 is a ligand for immunoglobulin-kappa promoter E-box elements. Biochem J 2001; 354:431-8. [PMID: 11171123 PMCID: PMC1221672 DOI: 10.1042/0264-6021:3540431] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Immunoglobulin (Ig)-kappa promoters from humans and mice share conserved sequences. The octamer element is common to all Ig promoters and pivotal for their function. However, other conserved sequence motifs, that differ between Ig variable gene families, are required for normal promoter function. These conserved motifs do not stimulate transcription in the absence of an octamer. One example is an E-box of the E47/E12 type (5'-CAGCTG-3'), which is found in all promoters of the human and murine Ig-kappa gene subgroups/families, with the exception of subgroups II and VI and their related murine families. In the present study we show that the ubiquitously expressed transcription factor AP-4, and not E47, interacts specifically with the kappa promoter E-boxes when tested in electrophoretic mobility-shift assays using nuclear extracts derived from human and murine B-cell lines. Furthermore, AP-4, unlike E47, did not act as a transactivator, which is in agreement with previous studies on intact kappa promoters, showing that transcription is absent when the octamer element has been mutated. Based on these data, and the conservation of the 5'-CAGCTG-3' motif among human and murine kappa promoters, we propose that AP-4 is the major ligand for Ig-kappa promoter E-boxes.
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Affiliation(s)
- A Aranburu
- Section for Immunology, Department of Cell and Molecular Biology, Lund University, BMC I13, S-22184 Lund, Sweden.
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