TY - JOUR
T1 - Tissue-specific regulation of the mouse αA-crystallin gene in lens via recruitment of Pax6 and c-Maf to its promoter
AU - Yang, Ying
AU - Cvekl, Ales
N1 - Funding Information:
The authors thank Dr T. Stopka for advice on qChIPs and help with quantitative analysis, and Drs S. Saule and L. Wolf for critical reading of this manuscript. We are grateful to Drs M. Dorrell, T. Kays and K. Mitton for retinal and corneal RNA samples. We thank Drs M. Busslinger, J. A. Epstein, A. Sharma, A. Swaroop and K. Yoshida for expression clones or cDNAs used in this study. We thank Dr S. Saule for anti-Pax6 antibody and A. Cvekl, Jr. for his assistance in editing the manuscript. We also acknowledge AECOM DNA sequencing core facility and use of the ABI 7900HT equipment. The work was supported from NIH grants, EY12200 and 14237.
PY - 2005/8/19
Y1 - 2005/8/19
N2 - Pax6 is a lineage-restricted DNA-binding transcription factor regulating the formation of mammalian organs including brain, eye and pancreas. Pax6 plays key roles during the initial formation of lens lineage, proliferation of lens progenitor and precursor cells and their terminal differentiation. In addition to Pax6, lens fiber cell differentiation is regulated by c-Maf, Prox1 and Sox1. Crystallins are essential lens structural proteins required for light refraction and transparency. Mouse αA-crystallin represents about 17% of all crystallins at the protein level and ranks as one of the most abundant tissue-specific proteins. Lens-specific expression of this gene is regulated at the level of transcription. A promoter fragment of -88 to +46 is capable of driving lens-specific expression in transgenic mouse. Here we provide data suggesting that this lens-specific promoter fragment is comprised of multiple Pax6 and Maf-binding sites. Site-directed mutagenesis of regions within these sites resulted in partially or completely reduced promoter activities in lens cells. Co-transfections using Pax6 and c-Maf alone revealed moderate and strong activations of this promoter, respectively. In contrast to synergistic activation of αB-crystallin by Pax6 and c-Maf, Pax6 has a neutral effect on c-Maf-mediated αA-crystallin promoter activation. Chromatin immunoprecipitations established in vivo interactions of Pax6 and c-Maf with the αA-crystallin promoter in lens cells. Collectively, the present data support a molecular model in which tissue-specific expression of αA-crystallin is regulated by recruitment of Pax6 and c-Maf, two proteins regulating multiple processes of lens differentiation, to its promoter. In addition, the data suggest a molecular model of temporal and spatial regulation of αB, αA and γ-crystallin genes in mouse embryonic lens by using variants of the Pax6/Maf regulatory module.
AB - Pax6 is a lineage-restricted DNA-binding transcription factor regulating the formation of mammalian organs including brain, eye and pancreas. Pax6 plays key roles during the initial formation of lens lineage, proliferation of lens progenitor and precursor cells and their terminal differentiation. In addition to Pax6, lens fiber cell differentiation is regulated by c-Maf, Prox1 and Sox1. Crystallins are essential lens structural proteins required for light refraction and transparency. Mouse αA-crystallin represents about 17% of all crystallins at the protein level and ranks as one of the most abundant tissue-specific proteins. Lens-specific expression of this gene is regulated at the level of transcription. A promoter fragment of -88 to +46 is capable of driving lens-specific expression in transgenic mouse. Here we provide data suggesting that this lens-specific promoter fragment is comprised of multiple Pax6 and Maf-binding sites. Site-directed mutagenesis of regions within these sites resulted in partially or completely reduced promoter activities in lens cells. Co-transfections using Pax6 and c-Maf alone revealed moderate and strong activations of this promoter, respectively. In contrast to synergistic activation of αB-crystallin by Pax6 and c-Maf, Pax6 has a neutral effect on c-Maf-mediated αA-crystallin promoter activation. Chromatin immunoprecipitations established in vivo interactions of Pax6 and c-Maf with the αA-crystallin promoter in lens cells. Collectively, the present data support a molecular model in which tissue-specific expression of αA-crystallin is regulated by recruitment of Pax6 and c-Maf, two proteins regulating multiple processes of lens differentiation, to its promoter. In addition, the data suggest a molecular model of temporal and spatial regulation of αB, αA and γ-crystallin genes in mouse embryonic lens by using variants of the Pax6/Maf regulatory module.
KW - Crystallins
KW - Differentiation
KW - Lens
KW - Pax6
KW - c-Maf
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U2 - 10.1016/j.jmb.2005.05.072
DO - 10.1016/j.jmb.2005.05.072
M3 - Article
C2 - 16023139
AN - SCOPUS:22544485368
SN - 0022-2836
VL - 351
SP - 453
EP - 469
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 3
ER -