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

Francis Poulat,Pascal De Santa Barbara,Marion Desclozeaux,Stephan Soullier,Brigitte Moniot,Nathalie Bonneaud,Brigitte Boizet,Philippe Berta

doi:10.1074/jbc.272.11.7167

Abstract

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.

Highlights

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 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]
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]

Summary

Introduction

Male sex determination is controlled by genetic information encoded on the Y chromosome and leads to the differentiation of embryonic gonads into testes. The human Y-linked testis determining gene SRY encodes a protein with a DNA binding domain from the high mobility group box family. We identify in a yeast two-hybrid screen a PDZ protein termed SIP-1, as an interacting protein with human SRY.

Results

Conclusion