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Tak HJ, Park TJ, Piao Z, Lee SH. Separate development of the maxilla and mandible is controlled by regional signaling of the maxillomandibular junction during avian development. Dev Dyn 2016; 246:28-40. [PMID: 27756109 DOI: 10.1002/dvdy.24465] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 10/10/2016] [Accepted: 10/14/2016] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Syngnathia is a congenital craniofacial disorder characterized by bony or soft tissue fusion of upper and lower jaws. Previous studies suggested some causative signals, such as Foxc1 or Bmp4, cause the disruption of maxillomandibular identity, but their location and the interactive signals involved remain unexplored. We wanted to examine the embryonic origin of syngnathia based on the assumption that it may be located at the separation between the maxillary and mandibular processes. This region, known as the maxillomandibular junction (MMJ), is involved in segregation of cranial neural crest-derived mesenchyme into the presumptive upper and lower jaws. RESULTS Here we investigated the role of Fgf, Bmp, and retinoid signaling during development of MMJ in chicken embryos. By changing the levels of these signals with bead implants, we induced syngnathia with microstomia on the treated side, which showed increased Barx1 and neural cell adhesion molecule (NCAM) expression. Redistribution of proliferating cells was also observed at the proximal region to maxillary and mandibular arch around MMJ. CONCLUSIONS We propose that interactive molecular signaling by Fgfs, Bmps, and retinoids around MMJ is required for normal separation of the maxilla and mandible, as well as the proper positioning of beak commissure during early facial morphogenesis. Developmental Dynamics 246:28-40, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Hye-Jin Tak
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea
| | - Tae-Jin Park
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea
| | - Zhenngu Piao
- Department of Oral and Maxillofacial Surgery, Stomatology Hospital of Guangzhou Medical College, GuangZhou City, China
| | - Sang-Hwy Lee
- Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.,Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea
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2
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Mi Y, Zhao S, Zhang W, Zhang D, Weng J, Huang K, Sun H, Tang H, Zhang X, Sun X, Peng Z, Wen Y. Down-regulation of Barx2 predicts poor survival in colorectal cancer. Biochem Biophys Res Commun 2016; 478:67-73. [DOI: 10.1016/j.bbrc.2016.07.091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 07/20/2016] [Indexed: 01/20/2023]
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Hulin JA, Nguyen TDT, Cui S, Marri S, Yu RT, Downes M, Evans RM, Makarenkova H, Meech R. Barx2 and Pax7 Regulate Axin2 Expression in Myoblasts by Interaction with β-Catenin and Chromatin Remodelling. Stem Cells 2016; 34:2169-82. [PMID: 27144473 PMCID: PMC5019118 DOI: 10.1002/stem.2396] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 02/15/2016] [Accepted: 04/14/2016] [Indexed: 12/13/2022]
Abstract
Satellite cells are the resident stem cells of skeletal muscle; quiescent in adults until activated by injury to generate proliferating myoblasts. The canonical Wnt signalling pathway, mediated by T-cell factor/lymphoid enhancer factor (TCF/LEF) and β-catenin effector proteins, controls myoblast differentiation in vitro, and recent work suggests that timely termination of the Wnt/β-catenin signal is important for normal adult myogenesis. We recently identified the Barx2 and Pax7 homeobox proteins as novel components of the Wnt effector complex. Here, we examine molecular and epigenetic mechanisms by which Barx2 and Pax7 regulate the canonical Wnt target gene Axin2, which mediates critical feedback to terminate the transcriptional response to Wnt signals. Barx2 is recruited to the Axin2 gene via TCF/LEF binding sites, recruits β-catenin and the coactivator GRIP-1, and induces local H3K-acetylation. Barx2 also promotes nuclear localization of β-catenin. Conversely, Pax7 represses Axin2 promoter/intron activity and inhibits Barx2-mediated H3K-acetylation via the corepressor HDAC1. Wnt3a not only induces Barx2 mRNA, but also stabilises Barx2 protein in myoblasts; conversely, Wnt3a potently inhibits Pax7 protein expression. As Barx2 promotes myogenic differentiation and Pax7 suppresses it, this novel posttranscriptional regulation of Barx2 and Pax7 by Wnt3a may be involved in the specification of differentiation-competent and -incompetent myoblast populations. Finally, we propose a model for dual function of Barx2 downstream of Wnt signals: activation of myogenic target genes in association with canonical myogenic regulatory factors, and regulation of the negative feedback loop that limits the response of myoblasts to Wnt signals via direct interaction of Barx2 with the TCF/β-catenin complex. Stem Cells 2016;34:2169-2182.
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Affiliation(s)
- Julie-Ann Hulin
- Department of Clinical Pharmacology, Flinders University, Bedford Park, South Australia, Australia
| | - Thi Diem Tran Nguyen
- Department of Clinical Pharmacology, Flinders University, Bedford Park, South Australia, Australia.,Centre for Cancer Biology, University of South Australia, Adelaide, South Australia, Australia
| | - Shuang Cui
- Department of Clinical Pharmacology, Flinders University, Bedford Park, South Australia, Australia
| | - Shashikanth Marri
- Department of Molecular Medicine, Flinders University, Bedford Park, South Australia, Australia
| | - Ruth T Yu
- Gene Expression Laboratory, Salk Institute, La Jolla, California, USA
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute, La Jolla, California, USA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute, La Jolla, California, USA.,Howard Hughes Medical Institute, Salk Institute, La Jolla, California, USA
| | - Helen Makarenkova
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Robyn Meech
- Department of Clinical Pharmacology, Flinders University, Bedford Park, South Australia, Australia
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4
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Zhuang L, Hulin JA, Gromova A, Tran Nguyen TD, Yu RT, Liddle C, Downes M, Evans RM, Makarenkova HP, Meech R. Barx2 and Pax7 have antagonistic functions in regulation of wnt signaling and satellite cell differentiation. Stem Cells 2015; 32:1661-73. [PMID: 24753152 DOI: 10.1002/stem.1674] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 12/16/2013] [Accepted: 01/16/2012] [Indexed: 11/05/2022]
Abstract
The canonical Wnt signaling pathway is critical for myogenesis and can induce muscle progenitors to switch from proliferation to differentiation; how Wnt signals integrate with muscle-specific regulatory factors in this process is poorly understood. We previously demonstrated that the Barx2 homeobox protein promotes differentiation in cooperation with the muscle regulatory factor (MRF) MyoD. Pax7, another important muscle homeobox factor, represses differentiation. We now identify Barx2, MyoD, and Pax7 as novel components of the Wnt effector complex, providing a new molecular pathway for regulation of muscle progenitor differentiation. Canonical Wnt signaling induces Barx2 expression in muscle progenitors and perturbation of Barx2 leads to misregulation of Wnt target genes. Barx2 activates two endogenous Wnt target promoters as well as the Wnt reporter gene TOPflash, the latter synergistically with MyoD. Moreover, Barx2 interacts with the core Wnt effectors β-catenin and T cell-factor 4 (TCF4), is recruited to TCF/lymphoid enhancer factor sites, and promotes recruitment of β-catenin. In contrast, Pax7 represses the Wnt reporter gene and antagonizes the activating effect of Barx2. Pax7 also binds β-catenin suggesting that Barx2 and Pax7 may compete for interaction with the core Wnt effector complex. Overall, the data show for the first time that Barx2, Pax7, and MRFs can act as direct transcriptional effectors of Wnt signals in myoblasts and that Barx2 and Wnt signaling participate in a regulatory loop. We propose that antagonism between Barx2 and Pax7 in regulation of Wnt signaling may help mediate the switch from myoblast proliferation to differentiation.
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Affiliation(s)
- Lizhe Zhuang
- Department of Clinical Pharmacology, Flinders University, Bedford Park, Adelaide, South Australia, Australia
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5
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Meech R, Gonzalez KN, Barro M, Gromova A, Zhuang L, Hulin JA, Makarenkova HP. Barx2 is expressed in satellite cells and is required for normal muscle growth and regeneration. Stem Cells 2012; 30:253-65. [PMID: 22076929 DOI: 10.1002/stem.777] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Muscle growth and regeneration are regulated through a series of spatiotemporally dependent signaling and transcriptional cascades. Although the transcriptional program controlling myogenesis has been extensively investigated, the full repertoire of transcriptional regulators involved in this process is far from defined. Various homeodomain transcription factors have been shown to play important roles in both muscle development and muscle satellite cell-dependent repair. Here, we show that the homeodomain factor Barx2 is a new marker for embryonic and adult myoblasts and is required for normal postnatal muscle growth and repair. Barx2 is coexpressed with Pax7, which is the canonical marker of satellite cells, and is upregulated in satellite cells after muscle injury. Mice lacking the Barx2 gene show reduced postnatal muscle growth, muscle atrophy, and defective muscle repair. Moreover, loss of Barx2 delays the expression of genes that control proliferation and differentiation in regenerating muscle. Consistent with the in vivo observations, satellite cell-derived myoblasts cultured from Barx2(-/-) mice show decreased proliferation and ability to differentiate relative to those from wild-type or Barx2(+/-) mice. Barx2(-/-) myoblasts show reduced expression of the differentiation-associated factor myogenin as well as cell adhesion and matrix molecules. Finally, we find that mice lacking both Barx2 and dystrophin gene expression have severe early onset myopathy. Together, these data indicate that Barx2 is an important regulator of muscle growth and repair that acts via the control of satellite cell proliferation and differentiation.
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Affiliation(s)
- Robyn Meech
- Department of Clinical Pharmacology, Flinders University, Bedford Park, South Australia, Australia
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6
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Makarenkova HP, Meech R. Barx homeobox family in muscle development and regeneration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 297:117-73. [PMID: 22608559 DOI: 10.1016/b978-0-12-394308-8.00004-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Homeobox transcription factors are key intrinsic regulators of myogenesis. In studies spanning several years, we have characterized the homeobox factor Barx2 as a novel marker for muscle progenitor cells and an important regulator of muscle growth and repair. In this review, we place the expression and function of Barx2 and its paralogue Barx1 in context with other muscle-expressed homeobox factors in both embryonic and adult myogenesis. We also describe the structure and regulation of Barx genes and possible gene/disease associations. The functional domains of Barx proteins, their molecular interactions, and cellular functions are presented with particular emphasis on control of genes and processes involved in myogenic differentiation. Finally, we describe the patterns of Barx gene expression in vivo and the phenotypes of various Barx gene perturbation models including null mice. We focus on the Barx2 null mouse model, which has demonstrated the critical roles of Barx2 in postnatal myogenesis including muscle maintenance during aging, and regeneration of acute and chronic muscle injury.
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Affiliation(s)
- Helen P Makarenkova
- The Neurobiology Department, Scripps Research Institute, La Jolla, California, USA
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7
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Meech R, Gomez M, Woolley C, Barro M, Hulin JA, Walcott EC, Delgado J, Makarenkova HP. The homeobox transcription factor Barx2 regulates plasticity of young primary myofibers. PLoS One 2010; 5:e11612. [PMID: 20657655 PMCID: PMC2904708 DOI: 10.1371/journal.pone.0011612] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 06/23/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Adult mammalian muscle retains incredible plasticity. Muscle growth and repair involves the activation of undifferentiated myogenic precursors called satellite cells. In some circumstances, it has been proposed that existing myofibers may also cleave and produce a pool of proliferative cells that can re-differentiate into new fibers. Such myofiber dedifferentiation has been observed in the salamander blastema where it may occur in parallel with satellite cell activation. Moreover, ectopic expression of the homeodomain transcription factor Msx1 in differentiated C2C12 myotubes has been shown to induce their dedifferentiation. While it remains unclear whether dedifferentiation and redifferentiaton occurs endogenously in mammalian muscle, there is considerable interest in induced dedifferentiation as a possible regenerative tool. METHODOLOGY/PRINCIPAL FINDINGS We previously showed that the homeobox protein Barx2 promotes myoblast differentiation. Here we report that ectopic expression of Barx2 in young immature myotubes derived from cell lines and primary mouse myoblasts, caused cleavage of the syncytium and downregulation of differentiation markers. Microinjection of Barx2 cDNA into immature myotubes derived from primary cells led to cleavage and formation of mononucleated cells that were able to proliferate. However, injection of Barx2 cDNA into mature myotubes did not cause cleavage. Barx2 expression in C2C12 myotubes increased the expression of cyclin D1, which may promote cell cycle re-entry. We also observed differential muscle gene regulation by Barx2 at early and late stages of muscle differentiation which may be due to differential recruitment of transcriptional activator or repressor complexes to muscle specific genes by Barx2. CONCLUSIONS/SIGNIFICANCE We show that Barx2 regulates plasticity of immature myofibers and might act as a molecular switch controlling cell differentiation and proliferation.
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Affiliation(s)
- Robyn Meech
- The Scripps Research Institute, La Jolla, California, United States of America
- The Flinders University of South Australia, Beford Park, South Australia, Australia
| | - Mariana Gomez
- The Scripps Research Institute, La Jolla, California, United States of America
| | - Christopher Woolley
- The Scripps Research Institute, La Jolla, California, United States of America
| | - Marietta Barro
- The Scripps Research Institute, La Jolla, California, United States of America
| | - Julie-Ann Hulin
- The Scripps Research Institute, La Jolla, California, United States of America
| | | | - Jary Delgado
- The Neurosciences Institute, San Diego, California, United States of America
| | - Helen P. Makarenkova
- The Scripps Research Institute, La Jolla, California, United States of America
- The Neurosciences Institute, San Diego, California, United States of America
- * E-mail:
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8
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Makarenkova HP, Gonzalez KN, Kiosses WB, Meech R. Barx2 controls myoblast fusion and promotes MyoD-mediated activation of the smooth muscle alpha-actin gene. J Biol Chem 2009; 284:14866-74. [PMID: 19269978 PMCID: PMC2685668 DOI: 10.1074/jbc.m807208200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 02/23/2009] [Indexed: 11/06/2022] Open
Abstract
Remodeling of the actin cytoskeleton is a critical early step in skeletal muscle differentiation. Smooth muscle alpha-actin (SMA) is one of the earliest markers of myoblast differentiation and is important for the migration and cell shape changes that precede fusion. We have found that satellite cell-derived primary myoblasts from mice lacking the Barx2 homeobox gene show altered patterns of actin remodeling, reduced cell migration, and delayed differentiation. Consistent with the role of SMA in these processes, Barx2(-)(/)(-) myoblasts also show reduced expression of SMA mRNA and protein. The proximal SMA promoter contains binding sites for muscle regulatory factors and serum response factor as well as a conserved homeodomain binding site (HBS). We found that Barx2 binds to the HBS element and potentiates up-regulation of SMA promoter activity by MyoD. We also show that Barx2, MyoD, and serum response factor simultaneously occupy the SMA promoter in cells and that Barx2 interacts with MyoD. Overall these data indicate that Barx2 cooperates with other muscle-expressed transcription factors to regulate the early cytoskeletal remodeling events that underlie efficient myoblast differentiation.
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Affiliation(s)
- Helen P Makarenkova
- Department of Neurobiology and Core Microscopy Facility, Scripps Research Institute, La Jolla, California 92037, USA
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9
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Sperber SM, Dawid IB. barx1 is necessary for ectomesenchyme proliferation and osteochondroprogenitor condensation in the zebrafish pharyngeal arches. Dev Biol 2008; 321:101-10. [PMID: 18590717 DOI: 10.1016/j.ydbio.2008.06.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 06/02/2008] [Accepted: 06/03/2008] [Indexed: 12/11/2022]
Abstract
Barx1 modulates cellular adhesion molecule expression and participates in specification of tooth-types, but little is understood of its role in patterning the pharyngeal arches. We examined barx1 expression during zebrafish craniofacial development and performed a functional analysis using antisense morpholino oligonucleotides. Barx1 is expressed in the rhombencephalic neural crest, the pharyngeal arches, the pectoral fin buds and the gut in contrast to its paralogue barx2, which is most prominently expressed in the arch epithelium. Additionally, barx1 transient expression was observed in the posterior lateral line ganglia and developing trunk/tail. We show that Barx1 is necessary for proliferation of the arch osteochondrogenic progenitors, and that morphants exhibit diminished and dysmorphic arch cartilage elements due to reductions in chondrocyte differentiation and condensation. Attenuation of Barx1 results in lost arch expression of osteochondrogenic markers col2a1, runx2a and chondromodulin, as well as odontogenic marker dlx2b. Further, loss of barx1 positively influenced gdf5 and chordin, markers of jaw joint patterning. FGF signaling is required for maintaining barx1 expression, and that ectopic BMP4 induces expression of barx1 in the intermediate region of the second pharyngeal arch. Together, these results indicate an essential role for barx1 at early stages of chondrogenesis within the developing zebrafish viscerocranium.
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Affiliation(s)
- Steven M Sperber
- Laboratory of Molecular Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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Slebos RJC, Yi Y, Ely K, Carter J, Evjen A, Zhang X, Shyr Y, Murphy BM, Cmelak AJ, Burkey BB, Netterville JL, Levy S, Yarbrough WG, Chung CH. Gene expression differences associated with human papillomavirus status in head and neck squamous cell carcinoma. Clin Cancer Res 2006; 12:701-9. [PMID: 16467079 DOI: 10.1158/1078-0432.ccr-05-2017] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Human papillomavirus (HPV) is associated with a subset of head and neck squamous cell carcinoma (HNSCC). Between 15% and 35% of HNSCCs harbor HPV DNA. Demographic and exposure differences between HPV-positive (HPV+) and negative (HPV-) HNSCCs suggest that HPV+ tumors may constitute a subclass with different biology, whereas clinical differences have also been observed. Gene expression profiles of HPV+ and HPV- tumors were compared with further exploration of the biological effect of HPV in HNSCC. Thirty-six HNSCC tumors were analyzed using Affymetrix Human 133U Plus 2.0 GeneChip and for HPV by PCR and real-time PCR. Eight of 36 (22%) tumors were positive for HPV subtype 16. Statistical analysis using Significance Analysis of Microarrays based on HPV status as a supervising variable resulted in a list of 91 genes that were differentially expressed with statistical significance. Results for a subset of these genes were verified by real-time PCR. Genes highly expressed in HPV+ samples included cell cycle regulators (p16(INK4A), p18, and CDC7) and transcription factors (TAF7L, RFC4, RPA2, and TFDP2). The microarray data were also investigated by mapping genes by chromosomal location (DIGMAP). A large number of genes on chromosome 3q24-qter had high levels of expression in HPV+ tumors. Further investigation of differentially expressed genes may reveal the unique pathways in HPV+ tumors that may explain the different natural history and biological properties of these tumors. These properties may be exploited as a target of novel therapeutic agents in HNSCC treatment.
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Affiliation(s)
- Robbert J C Slebos
- Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-6307, USA
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11
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Rachidi M, Lopes C. Differential transcription ofBarhl1homeobox gene in restricted functional domains of the central nervous system suggests a role in brain patterning. Int J Dev Neurosci 2005; 24:35-44. [PMID: 16384683 DOI: 10.1016/j.ijdevneu.2005.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 11/02/2005] [Accepted: 11/14/2005] [Indexed: 10/25/2022] Open
Abstract
The mouse Barhl1 homeogene, member of the BarH subfamily, play a crucial role in the cerebellum development and its human ortholog BARHL1 has been proposed as a positional and functional candidate gene for the Joubert syndrome, a form of cerebellar ataxia. The Barhl1 expression has been demonstrated to be induced by the transcription factor Math1 involved in BMP responses. We isolated the mouse Barhl1 by screening of a cDNA library with the Xenopus Xvent-2, member of the BarH subfamily, which acts in the BMP4 pathway during embryonic patterning and neural plate differentiation. We studied the detailed Barhl1 expression pattern and showed its transcription in spatio-temporally and functionally restricted domains of the developing central nervous system (CNS). Using our new optical microscopy technology, we compare the transcript steady state level and cell density in the Barhl1-expressing regions. We found that Barhl1 was transcribed in superior and inferior colliculi in the dorsal mesencephalon at a relatively low transcriptional level. In the diencephalon, Barhl1 was found higher expressed first within the basal plate and later in the mammillary region. In the cerebellum, Barhl1 showed the highest transcriptional level restricted to the anterior and posterior rhombic lips giving rise to the external and internal cerebellar granular cells and to the deep nuclei. In the spinal cord, Barhl1 showed similar expression level than in the cerebellum and is delimited to a subset of dorsal interneurons. Therefore, our results indicated that Barhl1 homeodomain gene is exclusively transcribed in restricted CNS domain at differential transcription levels which suggest a highly regulated transcriptional mechanism. In addition, these regional and cellular specificities indicated that Barhl1 may be involved in the differentiation of the specific subsets of neuronal progenitors.
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Affiliation(s)
- Mohammed Rachidi
- Institut d'Embryologie Cellulaire et Moléculaire, CNRS UMR 7128, Collège de France, 94736 Nogent-sur-Marne, France.
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Laifenfeld D, Karry R, Grauer E, Klein E, Ben-Shachar D. Antidepressants and prolonged stress in rats modulate CAM-L1, laminin, and pCREB, implicated in neuronal plasticity. Neurobiol Dis 2005; 20:432-41. [PMID: 15905095 DOI: 10.1016/j.nbd.2005.03.023] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 03/30/2005] [Accepted: 03/31/2005] [Indexed: 11/29/2022] Open
Abstract
Previously, we reported an ability of NE to promote processes of plasticity in neuroblastoma cells, as observed by morphological changes such as an elongated granule-rich cell body and neuritegenesis, in addition to a progressive decrease in the pluripotent marker Oct4 and an increase in the growth cone marker GAP-43. This was accompanied by the induction of three plasticity genes forming a functional cluster, the cell adhesion molecule L1 (CAM-L1), laminin, and CREB, all involved in neuronal plasticity and neurite outgrowth. In the present study, we hypothesized that the regulation of CAM-L1, laminin, and CREB/pCREB by NE could mediate processes of plasticity in the mode of action of antidepressants, as well as in the long-term effects of stress, in rats, given the association of both with NE alterations and neuronal plasticity. In the first experiment, rats were chronically administered with antidepressants (21 days). In the second experiment, rats were exposed to chronic stress and examined 4 months later, a model shown to exhibit behavioral indices of stress. We found brain region-specific alterations in mRNA and protein levels of CAM-L1, laminin, and pCREB in rats chronically treated with the noradrenergic antidepressant desipramine and, to a lesser extent, in those treated with fluoxetine. Stressed rats presented a decrease in CAM-L1, laminin, and pCREB, specifically in brain areas implicated in stress. Our findings suggest that noradrenergic-regulated plasticity genes such as CAM-L1, laminin, and CREB play an important role both in stress and in the treatment of depression.
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Affiliation(s)
- D Laifenfeld
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Medical Center and B. Rappaport Faculty of Medicine, Technion ITT, POB 9649 Haifa, 31096, Israel
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Sud R, Jones CM, Banfi S, Dawson SJ. Transcriptional regulation by Barhl1 and Brn-3c in organ of corti derived cell lines. ACTA ACUST UNITED AC 2005; 141:174-80. [PMID: 16226339 DOI: 10.1016/j.molbrainres.2005.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 08/22/2005] [Accepted: 09/05/2005] [Indexed: 11/30/2022]
Abstract
Barhl1 and Brn-3c have been identified as transcription factors that are essential for survival and maintenance of hair cells of the inner ear. Little is known about the mechanism of how Brn-3c or Barhl1 may regulate transcription in the inner ear. In this study, the transcriptional function of both Brn-3c and Barhl1 was investigated in the organ-of-Corti-derived cell lines, OC-1 and OC-2. We examined regulatory domains in these transcription factors by linking regions of Barhl1 and Brn-3c to the DNA binding domain of the heterologous transcription factor GAL4 and assayed their effect on a heterologous promoter containing GAL4 DNA binding sites by co-transfection into OC-1 and OC-2 cell lines. Brn-3c was found to contain an independent N-terminal activation domain that is sufficient to activate gene transcription in the organ of corti derived cell lines. Barhl1 on the other hand was found to act as a transcriptional repressor with repressive activity not restricted to a particular domain of Barhl1. In addition, we analyzed the effect of Barhl1 on the promoters of the neurotrophin genes NT-3 and BDNF in OC-1 and OC-2 cell lines. However, Barhl1 was not found to directly regulate neurotrophin promoter constructs in these cells.
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Affiliation(s)
- Richa Sud
- Molecular Audiology Group, Centre for Auditory Research, UCL Ear Institute, 332 Gray's Inn Rd, London WC1X 8EE, UK
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14
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Meech R, Edelman DB, Jones FS, Makarenkova HP. The homeobox transcription factor Barx2 regulates chondrogenesis during limb development. Development 2005; 132:2135-46. [PMID: 15800003 DOI: 10.1242/dev.01811] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Among the many factors involved in regulation of chondrogenesis, bone morphogenetic proteins (BMPs) and members of the Sox and homeobox transcription factor families have been shown to have crucial roles. Of these regulators, the homeobox transcription factors that function during chondrogenesis have been the least well defined. We show here that the homeobox transcription factor Barx2 is expressed in primary mesenchymal condensations, digital rays, developing joints and articular cartilage of the developing limb, suggesting that it plays a role in chondrogenesis. Using retroviruses and antisense oligonucleotides to manipulate Barx2 expression in limb bud micromass cultures, we determined that Barx2 is necessary for mesenchymal aggregation and chondrogenic differentiation. In accordance with these findings, Barx2 regulates the expression of several genes encoding cell-adhesion molecules and extracellular matrix proteins, including NCAM and collagen II (Col2a1) in the limb bud. Barx2 bound to elements within the cartilage-specific Col2a1 enhancer, and this binding was reduced by addition of Barx2 or Sox9 antibodies, or by mutation of a HMG box adjacent to the Barx2-binding element, suggesting cooperation between Barx2 and Sox proteins. Moreover, both Barx2 and Sox9 occupy Col2a1 enhancer during chondrogenesis in vivo. We also found that two members of the BMP family that are crucial for chondrogenesis, GDF5 and BMP4, regulate the pattern of Barx2 expression in developing limbs. Based on these data, we suggest that Barx2 acts downstream of BMP signaling and in concert with Sox proteins to regulate chondrogenesis.
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Affiliation(s)
- Robyn Meech
- The Neurosciences Institute 10640 John Jay Hopkins Drive, San Diego, CA 92121, USA
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Offner N, Duval N, Jamrich M, Durand B. The pro-apoptotic activity of a vertebrate Bar-like homeobox gene plays a key role in patterning the Xenopus neural plate by limiting the number of chordin- and shh-expressing cells. Development 2005; 132:1807-18. [PMID: 15772136 DOI: 10.1242/dev.01712] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Targeted disruption of effectors molecules of the apoptotic pathway have demonstrated the occurrence and magnitude of early programmed cell death (EPCD), a form of apoptosis that affects proliferating and newly differentiated cells in vertebrates, and most dramatically cells of the central nervous system (CNS). Little is known about the molecular pathways controlling apoptosis at these early developmental stages, as the roles of EPCD during patterning of the developing nervous system. We describe a new function, in Xenopus neurodevelopment, for a highly conserved homeodomain protein Barhl2. Barhl2 promotes apoptosis in the Xenopus neuroectoderm and mesoderm, acting as a transcriptional repressor, through a mechanism that cannot be attributed to an unspecific cellular stress response. We show that the pro-apoptotic activity of Barhl2 is essential during normal neural plate formation as it limits the number of chordin- and Xshh-expressing cells in the prospective notochord and floorplate, which act as organizing centers. Our findings show that Barhl2 is part of a pathway regulating EPCD. They also provide evidence that apoptosis plays an important role in regulating the size of organizing centers.
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Affiliation(s)
- Nicolas Offner
- Unité Rétrovirus et Transfert Génétique, INSERM (U622). Institut Pasteur, Paris, France
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16
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Abstract
The transactivation domain of the cAMP response element-binding protein (CREB) consists of two major domains. The glutamine-rich Q2 domain, which interacts with the general transcription factor TAFII130/135, is sufficient for the recruitment of a functional RNA polymerase II complex and allows basal transcriptional activity. The kinase-inducible domain, however, mediates signal-induced activation of CREB-mediated transcription. It is generally believed that recruitment of the coactivators CREB-binding protein (CBP) and p300 after signal-induced phosphorylation of this domain at serine-133 strongly enhances CREB-dependent transcription. Transcriptional activity of CREB can also be potentiated by phosphoserine-133-independent mechanisms, and not all stimuli that provoke phosphorylation of serine-133 stimulate CREB-dependent transcription. This review presents an overview of the diversity of stimuli that induce CREB phosphorylation at Ser-133, focuses on phosphoserine-133-dependent and -independent mechanisms that affect CREB-mediated transcription, and discusses different models that may explain the discrepancy between CREB Ser-133 phosphorylation and activation of CREB-mediated transcription.
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Affiliation(s)
- Mona Johannessen
- Department of Biochemistry, Institute of Medical Biology, University of Tromsø, N-9037, Norway
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17
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Chung CH, Parker JS, Karaca G, Wu J, Funkhouser WK, Moore D, Butterfoss D, Xiang D, Zanation A, Yin X, Shockley WW, Weissler MC, Dressler LG, Shores CG, Yarbrough WG, Perou CM. Molecular classification of head and neck squamous cell carcinomas using patterns of gene expression. Cancer Cell 2004; 5:489-500. [PMID: 15144956 DOI: 10.1016/s1535-6108(04)00112-6] [Citation(s) in RCA: 473] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 02/02/2004] [Accepted: 03/09/2004] [Indexed: 12/15/2022]
Abstract
The prognostication of head and neck squamous cell carcinoma (HNSCC) is largely based upon the tumor size and location and the presence of lymph node metastases. Here we show that gene expression patterns from 60 HNSCC samples assayed on cDNA microarrays allowed categorization of these tumors into four distinct subtypes. These subtypes showed statistically significant differences in recurrence-free survival and included a subtype with a possible EGFR-pathway signature, a mesenchymal-enriched subtype, a normal epithelium-like subtype, and a subtype with high levels of antioxidant enzymes. Supervised analyses to predict lymph node metastasis status were approximately 80% accurate when tumor subsite and pathological node status were considered simultaneously. This work represents an important step toward the identification of clinically significant biomarkers for HNSCC.
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Affiliation(s)
- Christine H Chung
- Division of Hematology/Oncology, Department of Medicine, Vanderbuilt-Ingram Cancer Center, Vanderbuilt University School of Medicine, Nashville, Tennessee 37232, USA
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18
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Laifenfeld D, Karry R, Grauer E, Klein E, Ben-Shachar D. ATF2, a member of the CREB/ATF family of transcription factors, in chronic stress and consequent to antidepressant treatment: animal models and human post-mortem brains. Neuropsychopharmacology 2004; 29:589-97. [PMID: 14647483 DOI: 10.1038/sj.npp.1300357] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The regulation of gene expression has been implicated in the etiology and treatment of depression. Transcription factors serve as the intermediates between intracellular cascades and gene expression, and may therefore be involved in the pathophysiology and pharmacotherapy of depression. We and others have previously reported an increase in the phosphorylation of the transcription factor cAMP response element binding protein (CREB) by antidepressants, alongside brain region-specific alterations in pCREB by stress. In the present study, we examined the expression of another member of the CREB/ATF family of transcription factors, ATF2, in the brains of rats chronically treated with two different antidepressants, and in rats 4 months after their exposure to prolonged stress. ATF2 phosphorylation was decreased by antidepressants and increased at the aftermath of prolonged stress, specifically in the frontal cortex. We also examined ATF2 expression in the ventral parieto-occipital region of post-mortem human brains of normal controls, depressed, bipolar, and schizophrenic patients, obtained from the Stanley Foundation Brain Consortium. No alterations were observed in the levels of ATF2. However, in the depressed group, the pATF2 levels were higher in unmedicated compared to medicated patients, suggesting an antidepressant-induced reduction in pATF2. We discuss the possible role of ATF2 in depression, and propose that an interplay between ATF2 and CREB, and possibly other transcription factors, determines the final gene expression pattern in the etiology and treatment of depression.
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Affiliation(s)
- D Laifenfeld
- Laboratory of Psychobiology, The Department of Psychiatry, Rambam Medical Center and B. Rappaport Faculty of Medicine, Technion IIT, Haifa, Israel
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19
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Stevens TA, Iacovoni JS, Edelman DB, Meech R. Identification of novel binding elements and gene targets for the homeodomain protein BARX2. J Biol Chem 2004; 279:14520-30. [PMID: 14744868 DOI: 10.1074/jbc.m310259200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BARX2 is a homeobox transcription factor that influences cellular differentiation in various developmental contexts. To begin to identify the gene targets that mediate its effects, chromatin immunoprecipitation (ChIP) was used to isolate BARX2 binding sites from the human MCF7 breast cancer cell line. Cloning and sequencing of BARX2-ChIP-derived DNA fragments identified 60 potential BARX2 target loci that were proximal to or within introns of genes involved in cytoskeletal organization, cell adhesion, growth factor signaling, transcriptional regulation, and RNA metabolism. The sequences of over half of the fragments showed homology with the mouse genome, and several sequences could be mapped to orthologous human and mouse genes. Binding of BARX2 to 21 genomic loci examined was confirmed quantitatively by replicate ChIP assays. A combination of sequence analysis and electrophoretic mobility shift assays revealed homeodomain binding sites within several fragments that bind to BARX2 in vitro. The majority of BARX2 binding fragments tested (14/19), also affected transcription in luciferase reporter gene assays. Mutation analyses of three fragments showed that their transcriptional activities required the HBS, and suggested that BARX2 regulates gene expression by binding to DNA elements containing paired TAAT motifs that are separated by a poly(T) sequence. Inhibition of BARX2 expression in MCF7 cells led to reduced expression of eight genes associated with BARX2 binding sites, indicating that BARX2 directly regulates their expression. The data suggest that BARX2 can coordinate the expression of a network of genes that influence the growth of MCF7 cells.
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Affiliation(s)
- Tracy A Stevens
- Department of Neurobiology, The Scripps Research Institute, La Jolla, California 92037, USA
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20
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Lim J, Choi KW. Bar homeodomain proteins are anti-proneural in the Drosophila eye: transcriptional repression of atonal by Bar prevents ectopic retinal neurogenesis. Development 2003; 130:5965-74. [PMID: 14573515 DOI: 10.1242/dev.00818] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Atonal (Ato)/Math (Mammalian atonal homolog) family proneural proteins are key regulators of neurogenesis in both vertebrates and invertebrates. In the Drosophila eye, Ato is essential for the generation of photoreceptor neurons. Ato expression is initiated at the anterior ridge of the morphogenetic furrow but is repressed in the retinal precursor cells behind the furrow to prevent ectopic neurogenesis. We show that Ato repression is mediated by the conserved homeobox proteins BarH1 and BarH2. Loss of Bar causes cell-autonomous ectopic Ato expression, resulting in excess photoreceptor clusters. The initial ommatidial spacing at the furrow occurs normally in the absence of Bar, suggesting that the ectopic neurogenesis within Bar mutant clones is not due to the lack of Notch (N)-dependent lateral inhibition. Targeted misexpression of Bar is sufficient to repress ato expression. Furthermore, we provide evidence that Bar represses ato expression at the level of transcription without affecting the expression of an ato activator, Cubitus interruptus (Ci). Thus, we propose that Bar is essential for transcriptional repression of ato and the prevention of ectopic neurogenesis behind the furrow.
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Affiliation(s)
- Janghoo Lim
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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21
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Foucher I, Montesinos ML, Volovitch M, Prochiantz A, Trembleau A. Joint regulation of the MAP1B promoter by HNF3beta/Foxa2 and Engrailed is the result of a highly conserved mechanism for direct interaction of homeoproteins and Fox transcription factors. Development 2003; 130:1867-76. [PMID: 12642491 DOI: 10.1242/dev.00414] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The MAP1B (Mtap1b) promoter presents two evolutionary conserved overlapping homeoproteins and Hepatocyte nuclear factor 3beta (HNF3beta/Foxa2) cognate binding sites (defining putative homeoprotein/Fox sites, HF1 and HF2). Accordingly, the promoter domain containing HF1 and HF2 is recognized by cerebellum nuclear extracts containing Engrailed and Foxa2 and has regulatory functions in primary cultures of embryonic mesmetencephalic nerve cells. Transfection experiments further demonstrate that Engrailed and Foxa2 interact physiologically in a dose-dependent manner: Foxa2 antagonizes the Engrailed-driven regulation of the MAP1B promoter, and vice versa. This led us to investigate if Engrailed and Foxa2 interact directly. Direct interaction was confirmed by pull-down experiments, and the regions participating in this interaction were identified. In Foxa2 the interacting domain is the Forkhead box DNA-binding domain. In Engrailed, two independent interacting domains exist: the homeodomain and a region that includes the Pbx-binding domain. Finally, Foxa2 not only binds Engrailed but also Lim1, Gsc and Hoxa5 homeoproteins and in the four cases Foxa2 binds at least the homeodomain. Based on the involvement of conserved domains in both classes of proteins, it is proposed that the interaction between Forkhead box transcription factors and homeoproteins is a general phenomenon.
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Affiliation(s)
- Isabelle Foucher
- CNRS UMR 8542, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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22
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Meech R, Makarenkova H, Edelman DB, Jones FS. The homeodomain protein Barx2 promotes myogenic differentiation and is regulated by myogenic regulatory factors. J Biol Chem 2003; 278:8269-78. [PMID: 12486129 DOI: 10.1074/jbc.m207617200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The homeobox protein Barx2 is expressed in both smooth and skeletal muscle and is up-regulated during differentiation of skeletal myotubes. Here we use antisense-oligonucleotide inhibition of Barx2 expression in limb bud cell culture to show that Barx2 is required for myotube formation. Moreover, overexpression of Barx2 accelerates the fusion of MyoD-positive limb bud cells and C2C12 myoblasts. However, overexpression of Barx2 does not induce ectopic MyoD expression in either limb bud cultures or in multipotent C3H10T1/2 mesenchymal cells, and does not induce fusion of C3H10T1/2 cells. These results suggest that Barx2 acts downstream of MyoD. To test this hypothesis, we isolated the Barx2 gene promoter and identified DNA regulatory elements that might control Barx2 expression during myogenesis. The proximal promoter of the Barx2 gene contained binding sites for several factors involved in myoblast differentiation including MyoD, myogenin, serum response factor, and myocyte enhancer factor 2. Co-transfection experiments showed that binding sites for both MyoD and serum response factor are necessary for activation of the promoter by MyoD and myogenin. Taken together, these studies indicate that Barx2 is a key regulator of myogenic differentiation that acts downstream of muscle regulatory factors.
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Affiliation(s)
- Robyn Meech
- Department of Neurobiology, The Scripps Research Institute, La Jolla, California 92037, USA.
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23
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Ko JY, Lee TC, Hsiao CF, Lin GL, Yen SH, Chen KY, Hsiung CA, Chen PJ, Hsu MM, Jou YS. Definition of three minimal deleted regions by comprehensive allelotyping and mutational screening of FHIT,p16(INK4A), and p19(ARF) genes in nasopharyngeal carcinoma. Cancer 2002; 94:1987-96. [PMID: 11932901 DOI: 10.1002/cncr.10406] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Recurrent deletion on a chromosomal location in tumor cells can be detected by frequent allelic loss and generally is considered to be an indication of the existence of a tumor suppressor gene (TSG) in the region. In the current study, using fluorescent-labeled, high-density microsatellite markers for allelotyping, the authors pinpointed three minimal deleted regions (MDRs) and screened mutations of putative TSGs on chromosomes 3, 9, and 11 in nasopharyngeal carcinoma (NPC) cases occurring in Taiwan. METHODS A total of 133 informative microsatellite markers were used on chromosomes 3, 9, and 11 with an average marker density of 4 centimorgans (cM) for the allelotyping of genomic DNAs isolated from NPC tissues and their corresponding lymphocytes in 48 patients. The correlation between allelic loss and the clinicopathologic parameters of NPC tissues was examined. In addition, putative TSGs including FHIT, p16(INK4a), and p19(ARF) were selected for mutation screening to investigate their potential participation in NPC tumorigenesis. RESULTS Of 3787 informative allelotyping data, 25 frequent allelic losses (or loss of heterozygosity [LOH]) in 13 cytogenetic loci were identified based on a deletion frequency that was greater than the average of allelic loss on that particular chromosome. Several significant associations were determined after statistical analysis of the correlation between allelic loss and clinicopathologic parameters. The allelic losses by D9S318 and D11S1304 were associated with N2/N3 (P = 0.035 and P = 0.005, respectively), and those by D9S905 and D11S1304 were associated with grouped American Joint Committee on Cancer (AJCC) Stage III/IV samples (P = 0.022 and P = 0.017, respectively) of NPC tissues. In addition, three MDRs were revealed on 3p25.3-24.1 (< 19 cM), 3p23-21.31 (< 9 cM), and 11q22.1-23.2 (< 8 cM). To examine somatic mutations in previously reported TSGs located near these frequent LOH loci, three candidate genes, p16(INK4a), p19(ARF), and FHIT, were analyzed. Point mutations in the coding region of FHIT and in the intron 1 splicing acceptor site of both p16(INK4a) and p19(ARF) were detected in NPC cell lines. Sequence analysis of both p16(INK4a) and p19(ARF) transcripts revealed that the point mutation resulted in skipping of exon 2 and the generation of shorter transcripts. CONCLUSIONS High-density allelotyping permitted the discovery of 3 MDRs on 3p25.3-24.1 (< 19 cM), 3p23-21.31 (< 9 cM), and 11q22.1-23.2 (< 8 cM) and a correlation was determined between allelic loss and clinicopathologic parameters of NPC tissues. More important, one somatic mutation in NPC cell lines on the intron 1/exon 2 splicing acceptor site of the INK4a/ARF locus was found to result in exon 2 skipping both p16(INK4a) and p19(ARF) transcripts, which presumably inactivates the functions of both the p16(INK4a) and p19(ARF) proteins.
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MESH Headings
- Acid Anhydride Hydrolases
- Alleles
- Chromosome Aberrations
- Chromosome Deletion
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, Pair 3/genetics
- Chromosomes, Human, Pair 9/genetics
- Cyclin-Dependent Kinase Inhibitor p16/genetics
- DNA Mutational Analysis
- DNA, Neoplasm/analysis
- Genes, Tumor Suppressor
- Humans
- Loss of Heterozygosity
- Microsatellite Repeats/genetics
- Nasopharyngeal Neoplasms/genetics
- Nasopharyngeal Neoplasms/pathology
- Neoplasm Proteins/genetics
- Neoplasm Recurrence, Local/genetics
- Neoplasm Recurrence, Local/pathology
- Neoplasm Staging
- Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Tumor Suppressor Protein p14ARF/genetics
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Affiliation(s)
- Jenq-Yuh Ko
- Department of Otolaryngology, College of Medicine, National Taiwan University, Taipei, Taiwan
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24
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Herring BP, Kriegel AM, Hoggatt AM. Identification of Barx2b, a serum response factor-associated homeodomain protein. J Biol Chem 2001; 276:14482-9. [PMID: 11278942 DOI: 10.1074/jbc.m011585200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CC(A/T)(6)GG or serum response elements represent a common regulatory motif important for regulating the expression of many smooth muscle-specific genes. They are multifunctional elements that bind serum response factor (SRF) and are important for serum induction of genes, expression of muscle-specific genes, and differentiation of vascular smooth muscle cells. In the current study, a yeast two-hybrid screen was used to identify proteins from mouse intestine that interact with SRF. A novel homeodomain-containing transcription factor, called Barx2b, was identified that specifically interacts with SRF and promotes the DNA binding activity of SRF. Northern blotting, RNase protection analysis, and Western blotting revealed that Barx2b mRNA and protein are expressed in several smooth muscle-containing tissues, as well as in skeletal muscle and brain. In vitro binding studies using bacterial fusion proteins revealed that the DNA-binding domain of SRF interacts with a region of Barx2b located amino-terminal of the homeobox domain. The results of these studies support the hypothesis that interaction of SRF with different homeodomain-containing proteins may play a critical role in determining the cell-specific functions of SRF.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Western
- Brain/metabolism
- Cell Differentiation
- Cell Line
- DNA/metabolism
- DNA, Complementary/metabolism
- DNA-Binding Proteins/metabolism
- Electrophoresis, Polyacrylamide Gel
- Gene Library
- Genes, Reporter
- Homeodomain Proteins/biosynthesis
- Homeodomain Proteins/chemistry
- Homeodomain Proteins/metabolism
- Intestinal Mucosa/metabolism
- Mice
- Models, Genetic
- Molecular Sequence Data
- Muscle, Skeletal/metabolism
- Muscle, Smooth/metabolism
- Nuclear Proteins/metabolism
- Protein Binding
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/metabolism
- Recombinant Proteins/metabolism
- Ribonucleases/metabolism
- Sequence Homology, Amino Acid
- Serum Response Factor
- Time Factors
- Tissue Distribution
- Two-Hybrid System Techniques
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Affiliation(s)
- B P Herring
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis 46202-5120, USA.
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