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Distinct roles of SOX2, Pax6 and Maf transcription factors in the regulation of lens‐specific δ 1‐crystallin enhancer
Author(s) -
Muta Mayumi,
Kamachi Yusuke,
Yoshimoto Aki,
Higashi Yujiro,
Kondoh Hisato
Publication year - 2002
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.2002.00560.x
Subject(s) - biology , pax6 , enhancer , crystallin , transcription factor , sox2 , lens (geology) , transcription (linguistics) , microbiology and biotechnology , computational biology , genetics , gene , linguistics , philosophy , paleontology
Background: The eye lens provides a good model for the study of regulation of cell differentiation, in which lens‐specific δ 1‐crystallin expression serves as an indicator of the differentiated state of the cells. It has been indicated that the SOX2, Pax6 and Maf proteins are the major regulators of lens cell differentiation. To clarify the individual roles of these transcription factors, we analysed their participation in regulation of the δ 1‐crystallin enhancer. Results: We defined the major binding sites of SOX2, Pax6 and Maf transcription factors in the δ 1‐crystallin enhancer and assessed the effect of mutations at these sites in the cultured lens epithelial cells and in developing lenses of transgenic mouse embryos. SOX2 (or SOX1/SOX3) is essential for activation of the enhancer under all conditions. Pax6 bound at the δEF3 site is required for activation of the enhancer, while Pax6 at the Pax6U site appears to be involved in the Pax6‐dependent suppression of the enhancer. In contrast, Maf proteins are only required for high enhancer activity in lens fibre cells. Conclusion: The distinct roles of these transcription factors in the regulation of δ 1‐crystallin enhancer would tend to indicate their individual functions in lens differentiation. The activity of SOX2 and the related SOX1/3 is essential at all stages of lens development as transcriptional activators. Pax6, although it is required in all steps, probably exerts complex regulatory effects, since it possesses both the potential to activate and repress. The major function of Maf proteins presumably resides in the activation of the genes in lens fibre cells.