Rabbit polyclonal antibody to CstF~64 (R46)

CstF~64 contains an RNA binding domain and is responsible for the RNA binding activity of CstF. CstF~64 is expressed in all somatic cells and in pre~ and postmeiotic, but not meiotic, germ cells. However, a large variant of CstF~64, called t CstF~64, is abundantly expressed in meiotic and postmeiotic cells in the testis and to a lesser extent in the brain, and promotes the germ cell pattern of polyadenylation. The gene encoding CstF~64 (designated CSTF2) maps to the X chromosome, whereas t CstF~64 is encoded by an autosomal gene. The increase in CstF~64 concentration during B cell activation switches IgM heavy chain mRNA expression from membrane~bound to secreted forms, suggesting that CstF~64 plays a key role in regulating IgM heavy chain expression during B cell differentiation.