Involvement of SOX proteins in lens-specific activation of crystallin genes.

Kamachi, Yusuke; Sockanathan, Shanthini; Liu, Qiurong; Breitman, Martin L.; Lovell-Badge, Robin; Kondoh, Hisato

doi:10.1002/j.1460-2075.1995.tb07357.x

Cited by 231 publications

(160 citation statements)

References 37 publications

(62 reference statements)

Supporting

Mentioning

154

Contrasting

Order By: Relevance

“…Synergism between different transcription factors, some of them ubiquitous and some of them cell type specific, is required to achieve this precise regulation. In fact, non-lens-specific transcription factors are involved in lens-specific expression of several crystallin genes (8)(9)(10)(11)14). Here we report that Sp1 and AP2, two transcription factors that are not lens specific, interact with the MIP gene promoter, which is activated only in the lens.…”

Section: Discussionmentioning

confidence: 74%

“…Pax-6, a paired domain and homeodomain-containing protein, which is encoded by a master gene in eye formation and belongs to the PAX family of transcription factors, interacts with control elements present in the 5′-flanking region of the αA-, δ1-and ζ-crystallin genes (8,9,10). The Sox-2 transcription factor, which belongs to a protein family containing the HMG domain, functions as an activator of chicken δ1-and mouse γF-crystallin gene expression in the lens (11). Neither Pax-6 nor Sox-2 are lens specific.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Overlapping Sp1 and AP2 binding sites in a promoter element of the lens-specific MIP gene

Ohtaka-Maruyama

Wang

et al. 1998

Nucleic Acids Research

View full text Add to dashboard Cite

The MIP gene, the founder of the MIP family of channel proteins, is specifically expressed in fiber cells of the ocular lens and expression is regulated temporally and spatially during development. We previously found that a DNA fragment containing 253 bp of 5′-flanking sequence and 42 bp of exon 1 of the human MIP gene contains regulatory elements responsible for lensspecific expression of the MIP gene. In this report we have analyzed the function of overlapping Sp1 and AP2 binding sites present in the MIP promoter. Using DNase I footprinting analysis we found that purified Sp1 and AP2 transcription factors interact with several domains of the human MIP promoter sequence -253/+42. Furthermore, addition of purified Sp1 to Drosophila nuclear extracts activates in vitro transcription from the MIP promoter -253/+42. This promoter activity is competed by oligonucleotides containing domains footprinted with Sp1. Using promoter-reporter gene (CAT) constructs we found that the sequence -39/-70 contains a cis regulatory element essential for promoter activity in transient assays in lens cells. EMSA analysis showed that lens nuclear extracts contain factors that bind to the MIP 5′-flanking sequence containing overlapping Sp1 and AP2 binding domains at positions -37/-65. Supershift experiments with lens nuclear extracts indicated that Sp3 is also able to interact with this regulatory element, suggesting that Sp1 and Sp3 may be involved in regulation of transcription of the MIP gene in the lens.

show abstract

Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Overlapping Sp1 and AP2 binding sites in a promoter element of the lens-specific MIP gene

Ohtaka-Maruyama

Wang

et al. 1998

Nucleic Acids Research

View full text Add to dashboard Cite

show abstract

“…Finally, the NR domain fused to the Gal4 DNA binding domain repressed the HSV thymidine kinase promoter having Gal4 binding sites in an upstream position. The d1-crystallin enhancer fragment HN used in the assay is activated by a factor binding to the DC17 portion of the fragment (Funahashi et al 1991; in addition to dEF2 (Sox2, Kamachi et al 1995) and dEF3, and these factors are probably the target of repression.…”

Section: Two Mechanisms In the Action Of Repressor Def1mentioning

confidence: 99%

Two mechanisms in the action of repressor δEF1: binding site competition with an activator and active repression

et al. 1997

View full text Add to dashboard Cite

Background: Counteraction between activators and repressors is crucial for the regulation of a number of cell-specific enhancers, where an activator and a repressor are mutually competitive in binding to the same site. dEF1 is a repressor protein of d1-crystallin minimal enhancer DC5 binding at the CACCT site, and inhibits activator dEF3 from binding to the overlapped site. It has two zinc finger clusters N-fin and C-fin, close to N-and C-termini, respectively, and a homeodomain in the middle. dEF1 also binds to the E2-box sequence CACCTG, and represses E2-box-dependent enhancers.

show abstract

“…To date, no function has been ascribed to the regions of the human SRY protein outside the HMG box, whereas in mouse Sry, the Cterminal part of the protein can function as a transcriptional activator (6). This apparent lack of human SRY transactivation domain and the background-dependent sex determination capabilities of certain mouse Y chromosomes (7) along with the growing list of HMG box containing proteins involved in the assembly of multiprotein complexes (8,9) suggest that SRY might interact with other proteins. Indeed regulation of target genes by SRY may require collaboration with other factors interacting directly with the SRY protein.…”

mentioning

confidence: 99%

The Human Testis Determining Factor SRY Binds a Nuclear Factor Containing PDZ Protein Interaction Domains

Poulat

Barbara

Desclozeaux

et al. 1997

Journal of Biological Chemistry

144

View full text Add to dashboard Cite

The human Y-linked testis determining gene SRY encodes a protein with a DNA binding domain from the high mobility group box family. To date, no function has been assigned to amino acid sequences located outside this DNA binding motif. Here, we identify in a yeast two-hybrid screen a PDZ protein termed SIP-1, as an interacting protein with human SRY. In vitro, biochemical analysis, immunoprecipitation experiments, as well as expression of SIP-1 in human embryonic testis confirm that the two proteins can interact together. Interacting domains were mapped to the C-terminal seven amino acids of SRY and to the PDZ domains of SIP-1, respectively. We hypothesize that SIP-1 could connect SRY to other transcription factors providing SRY for its missing trans-regulation domain.In mammals, male sex determination is controlled by genetic information encoded on the Y chromosome and leads to the differentiation of embryonic gonads into testes. SRY, a Y-specific gene cloned in 1990 (1), was shown to meet all of the criteria of the testis determining factor (2, 3). SRY encodes a small nuclear protein of 204 residues comprising three distinct domains, with a central domain of about 78 amino acids called the high mobility group (HMG) 1 box. This central domain includes a nuclear localization signal (4), and in vitro studies of the human SRY protein have demonstrated its sequence-specific DNA binding through this HMG box (5). To date, no function has been ascribed to the regions of the human SRY protein outside the HMG box, whereas in mouse Sry, the Cterminal part of the protein can function as a transcriptional activator (6). This apparent lack of human SRY transactivation domain and the background-dependent sex determination capabilities of certain mouse Y chromosomes (7) along with the growing list of HMG box containing proteins involved in the assembly of multiprotein complexes (8, 9) suggest that SRY might interact with other proteins. Indeed regulation of target genes by SRY may require collaboration with other factors interacting directly with the SRY protein. Here, using the two-hybrid system we show that a PDZ domain containing nuclear protein interacts with the C-terminal portion of nonrodent SRY. Our two-hybrid results were confirmed by in vitro experiments and by immunoprecipitation that demonstrate that SRY and SIP-1 are associated also in vivo. Finally, immunofluorescence experiments reveal a nuclear expression pattern for SIP-1 in a cell line as well as in human embryo cuts at the level of the genital ridges. These results suggest a model in which SIP-1 could permit to connect SRY to another protein harboring a PDZ binding motif. The nature of this other protein partner and the functional implication of such a complex in human sex determination are now under investigation. MATERIALS AND METHODSLibrary Screenings-Yeast two-hybrid screening was carried out using the HF7c yeast strain harboring HIS3 and ␤-gal reporter genes under the control of upstream GAL4-binding sites as originally described (10, 11). The bait cons...

show abstract

Involvement of SOX proteins in lens-specific activation of crystallin genes.

Cited by 231 publications

References 37 publications

Overlapping Sp1 and AP2 binding sites in a promoter element of the lens-specific MIP gene

Overlapping Sp1 and AP2 binding sites in a promoter element of the lens-specific MIP gene

Two mechanisms in the action of repressor δEF1: binding site competition with an activator and active repression

The Human Testis Determining Factor SRY Binds a Nuclear Factor Containing PDZ Protein Interaction Domains

Contact Info

Product

Resources

About