Functional Research Of ASH2L And Interaction Protein DPY-30-like

The members of TrxG family contain PHD domain, which linked to leukemia genesis and was named as leukemia-associated-protein, LAP. Several members of this group also have SET domain, which can covalently modify histone and then open/close the gene expression in nearby region. That is the core of Epigenetic Developmental control.Our research group had cloned a new TrxG group member containing a PHD domain, ASH2L (Absent small homeotic 2 like). This gene is high homologous to Ash2 of several speices, such as yeast, drosaphila, and C. elegans. In human, ASH2L is highly expressed in bone marrow, fetal liver and Peripheral blood white cells, and also highly expressed in cell lines from leukemia. When K562 cells were stimulated by PMA, the expression of ASH2L is rapidly down regulated. All these showed that ASH2L importantly function in leucocyte differentiation. But the function mechanism of ASH2L is still unkown, it will be meaningful to find out the molecular mechanism of ASH2L.The searching of interaction protein of ASH2L may figure out the function clue. So, after screening HeLa cell library by yeast two-hybrid, an interaction protein was found: the homology of C. eleganse DPY-30-like, a member of X Chromosome dosage compensation. DPY-30-like is highly conserved in different spices. By in vitro pulldown assay, co-immunoprecipitation and immuno-fluorescence Confocal, interaction between ASH2L and DPY-30-like was verified. The results showed the interaction is real in vivo and in vitro.In order to learn the detail of interaction of ASH2L and DPY-30-like, the different fragment of ASH2L and DPY-30-like is inserted into expression vector and expressed. The truncation is based on the domain (PHD, SPRY in ASH2L and Dpy-30 motif in DPY-30-like). A series of pulldown experiments employing these different truncations reveal that the interaction take place on the C-terminal of both proteins and is not related to PHD domain.It is found by bioinformatics that ASH2L is divided into two genes, which contains PHD and SPRY domain separately. The two genes and DPY-30 are the components of yeast SETl complex bearing histone 3 N-lysine 4 methylation activity. So, in human body, ASH2L and DPY-30-like may be the member of SET1-like complex. In fact, several group have...