FERT ENCODES A MEIOSIS-SPECIFIC NUCLEAR TYROSINE KINASE

ferT is a mouse testis-specific mRNA, shown previously to potentially encode a 51 kilodalton tyrosine kinase termed p51ferT. The accumulatio n of ferT RNA is restricted to primary spermatocytes that are at the p rophase stage of the first spermatogenic meiotic division. By using an tibodies raised against a synthetic peptide which was designed accordi ng to a putative p51ferT unique amino acid sequence, we have shown tha t testicular cells indeed contain a 51 kilodalton protein that is reco gnized by the anti-p51ferT antibodies. The protein was not detected in six nontesticular mouse tissues, nor was it detected, like the ferT R NA, in the testes of 14-day-old mice. These findings strongly suggest that the 51 kilodalton protein is p51ferT. Immunohistochemical stainin g localized p51ferT to meiotically dividing spermatocytes. Transfectio n experiment in CHO cells confirmed the nuclear localization of p51fer T in eukaryotic cells. p51ferT seems thus to be the first meiosis-spec ific nuclear tyrosine kinase described to date.