title: Mafs, Prox1, and Pax6 can regulate chicken betaB1-crystallin gene expression.
abstract: During lens fiber cell differentiation, the regulation of crystallin gene expression is coupled with dramatic morphological changes. Here we report that Mafs, Prox1, and Pax6, which are essential transcription factors for normal lens development, bind to three functionally important cis elements, PL1, PL2, and OL2, in the chicken betaB1-crystallin promoter and may cooperatively direct the transcription of this lens fiber cell preferred gene. Gel shift assays demonstrated that Mafs bind to the MARE-like sequences in the PL1 and PL2 elements, whereas Prox1, a sequence-specific DNA-binding protein like its Drosophila homolog Prospero, interacts with the OL2 element. Furthermore, Pax6, a known repressor of the chicken betaB1-crystallin promoter, binds to all three of these cis elements. In transfection assays, Mafs and Prox1 activated the chicken betaB1-crystallin promoter; however, their transactivation ability was repressed when co-transfected with Pax6. Taken together with the known spatiotemporal expression patterns of Mafs, Prox1, and Pax6 in the developing lens, we propose that Pax6 occupies and represses the chicken betaB1-crystallin promoter in lens epithelial cells, and is displaced by Prox1 and Mafs, which activate the promoter, in differentiating cortical fiber cells.
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware 19716, USA.
authors.forename: Wenwu
authors.initials: W
authors.lastname: Cui
authors.forename: Stanislav I
authors.initials: SI
authors.lastname: Tomarev
authors.forename: Joram
authors.initials: J
authors.lastname: Piatigorsky
authors.forename: Ana B
authors.initials: AB
authors.lastname: Chepelinsky
authors.forename: Melinda K
authors.initials: MK
authors.lastname: Duncan
mesh_terms: D000818:Animals; D001483:Base Sequence; D002645:Chickens; D003459:Crystallins / Q000235:genetics*; D017931:DNA Primers; D005136:Eye Proteins; D020869:Gene Expression Profiling; D018398:Homeodomain Proteins / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000502:physiology*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D025521:Tumor Suppressor Proteins; D000098551:Prospero-Related Homeobox 1 Protein
chemical_list: D003459:Crystallins; D017931:DNA Primers; D005136:Eye Proteins; D018398:Homeodomain Proteins; D008869:Microtubule-Associated Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D025521:Tumor Suppressor Proteins; C085284:microtubule-associated protein 1B; D000098551:Prospero-Related Homeobox 1 Protein