The gene CSTF2T, encoding the human variant CstF-64 polyadenylation protein tauCstF-64, lacks introns and may be associated with male sterility.

Messenger RNA polyadenylation in male germ cells does not seem to require the AAUAAA polyadenylation signal required in all other cell types. To account for this difference, we found a variant form of the polyadenylation protein, the 64,000 Mr protein of the cleavage stimulation factor (CstF-64), in mouse meiotic and postmeiotic germ cells. This protein is a candidate to alter polyadenylation in those cells. More recently, we reported the cloning from mouse pachytene spermatocytes of mouse tauCstF-64 (gene symbol Cstf2t), which is a homolog of CstF-64 fitting the criteria we expected for the variant CstF-64 protein. Here we report the cloning and mapping of the human ortholog of mouse tauCstF-64. The human tauCstF-64 cDNA (gene symbol CSTF2T) is 2324 bp in length and encodes a protein of 616 amino acids (64,442.90 Da). Although most highly related to mouse tauCstF-64 (89.8% identity), human tauCstF-64 is also related to the human and mouse somatic CstF-64 (74.9% and 73.4% identity, respectively). Alignment of human tauCstF-64 with human genome sequence from chromosome 10 shows that CSTF2T lacks introns. Radiation hybrid mapping places the human tauCstF-64 gene at 10q22-q23, which is the site of a translocation that has been associated with human neurological problems and male infertility.