SF1 contains 1 CCHC-type zinc finger and 1 KH domain. SF1 is Necessary for the ATP-dependent first step of spliceosome assembly. It binds to the intron branch point sequence (BPS) 5'-UACUAAC-3' of the pre-mRNA. SF1 may act as transcription repressor.This gene encodes a member of the heat shock factor (HSF) family of transcriptional activators for heat shock proteins. This gene is a candidate gene for azoospermia, since it localizes to a region of chromosome Y that is sometimes deleted in infertile males. The genome has two identical copies of this gene within a palindromic region; this record represents the more centromeric copy. Alternative splicing results in multiple transcript variants encoding distinct isoforms.