A Nervous System, High Expression The Protein Bex1 Interacting With Protein Hsnf5 Function

By the screening of human fetal cDNA library, a cDNA clone named bex1(brain expressed X-link) was obtained. This cDNA is 791bp in length with a open reading frame of 358bp encoding 125 amino acids. Sequence alignment reveals that the identity of human BEX1 and mouse BEX1 is 65.89% for amino acids. We compared the homology of amino acid sequences of human BEX1 with other members of mouse Bex family and found that it has69.77% identity with mouse Bex2 and 29.93% with Bex3. The human bex1 gene , as well as its homology mouse bex1, bex2 and bex3, are highly expressed in the brain and all mapped to chromosome X(Xq22). We can not find any known domains in BEX1, but we notice that the C-terminus of it is similar to p75NTR-associated cell death executer, which is also highly expressed in brain and X-link. It may be a signaling adaptor molecule involved in p75NTR-apoptosis induced by nerve growth factor. So we hypothesize BEX1 may also act as an adaptor molecule and involve in the interaction of protein and protein. Other ground had reported that the level of mouse bex1 mRNA differenced with the development stage of testis, but nothing had been known about its functions in brain.We cloned the mouse BEX1 gene and characterization of its expression pattern in the mouse central nervous system. In situ hybridization with mouse brain sections, we found that BEX1 is highly expressed in hippocampus, there are strong signals distributed in all of the four sub-areas. In Northern blot of mouse fetal, the level of bex1 mRNA changes with the difference stage of development. This suggest that BEX1 may have important functions in the brain development.To determine the function of human BEX1 in brain, yeast two-hybrid systems was used to screen a human fetal cDNA library to search for the potential protein that can interact with BEX1. The result showed that hSNF5, a key member of human SWI/SNF chromatin remodeler, may be a protein interacting with BEX1.To confirm the interaction between BEX1 and hSNF5, we carried out GST-pull down...