The absorbance pattern after substrate depletion was observed by measuring absorbance change

A fragment of SCAI comprising amino acids 35�C280 was used as bait protein. SCAI-interacting proteins in high salt fraction of mouse brain lysate were separated and analyzed by mass spectroscopy analysis. The data showed proteins, mainly involved in histone modifications and having ATPase and DNA buy SNG-1153 helicase activities. Among these, 6 subunits of the SWI/SNF complex associated with SCAI. We were able to further confirm this potential interaction by coimmunoprecipitation experiments. SCAI and BRM, the central core ATPase subunit of the human SWI/SNF complex, were expressed in HEK 293 cells. SCAI was immunoprecipitated and the precipitates were analyzed for the presence of BRM. Interestingly, the N-terminal fragment comprising amino acids 1�C212, a region that we have previously characterized as a critical region for its biologically activity, was sufficient and required for interaction with BRM, whereas a construct lacking the N-terminus did not co-immunoprecipitated with BRM. We were also able to map the N-terminal 360 amino acids of BRM as the region required and sufficient to interact with SCAI by co-immunoprecipitation experiments. However, we have not been able to see association of endogenous BRM and SCAI, indicating that SCAI could be a substoichiometric, nonobligate partner for BRM and that this complex is only operative at certain promoters. Our data further indicate that SCAI requires the presence of a functional SWI/SNF complex to suppress promoter activity. We performed SRF-dependent reporter gene assays in SW13 cells, a human adrenal adenocarcinoma cell line that lacks expression of BRM and the closely related BRG1 protein. Transfection of an active version of the SRF co-activator MAL induced reporter gene activity in these cells, however, unlike to cell lines expressing BRM, the co-expression of SCAI did not affect the MAL-induced reporter gene activity in these cells, indicating that SCAI may be functionally dependent on SWI/1198097-97-0 SNF-activity to mediate changes in gene expression. We could further show that the expression of an ATPase-deficient mutant of BRM can relieve the inhibition of SCAI on MALind