A GERM CELL-SPECIFIC NUCLEAR ANTIGEN RECOGNIZED BY A MONOCLONAL-ANTIBODY RAISED AGAINST MOUSE TESTICULAR GERM-CELLS

A monoclonal antibody (mAb TRA104) raised against mouse testicular ger m cells was able to recognize the nuclei of testicular germ cells at a ll the stages of differentiation from embryonic gonocytes to spermatid s and did not react with any somatic cells. The antigen recognized by mAb TRA 104 was exclusively present in testicular extracts. The molecu lar weights and isoelectric point (pI) of the antigens determined by W estern blotting analysis were 60-110 kDa and 7.2, respectively. This a ntigen(s) is referred to as a germ cell-specific nuclear antigen(s) (G ENA) since GENA was first detected specifically in the genital ridge a t around 12 days of gestation by Western blotting analysis. In the tes tis, the expression increased gradually until adulthood whereas it was lost in the ovary by postpartum day 5. Thus, GENA is a molecule(s) ex clusively present in the nuclei of germ cells and may be a useful mark er with which to study the mechanism of germ cell development and diff erentiation at the molecular level.