OBJECTIVETo characterize the structural and the functional feature of a novel gene HSPCSET isolated from human CD34+ hematopoietic stem/progenitor cells (HS/PCs).

METHODSBioinformatic technology was used to identify the structural features of the HSPCSET protein and perform the multiple sequence alignment. Yeast-two-hybrid system was used to identify the proteins interacting with the HSPCSET protein. After sequencing, we selected out the positive clones which had clear functions, and carried out beta-gal experiment and GST pull down assay to confirm the results. The cellular location of the HSPCSET was checked by immunofluorescence assay.

RESULTSThe HSPCSET protein belongs to a SET domain family, which is evolutionarily conserved across species. It implied that HSPCSET may have biologically important function. Using yeast-two-hybrid system, we showed that the protein sequence with SET domain might bind to 13 proteins, which involved in signaling transduction, transcriptional regulation, apoptosis, tumorigenesis, development, etc. And 4 proteins (GADD34, SIVA, DNAJ and PHF1) were confirmed by one-on-one back of the hybrid experiment, beta-gal test and GST pull down assay. When GADD34 and HSPCSET were co-transfected, they co-localized in the nucleus, suggesting a strong interaction.

CONCLUSIONThe novel gene HSPCSET is likely to have biologically important function. This study provides the basis for further studies of its function in hematopoiesis and tumorigenesis.