Transgenic Rescue of Spermatogenesis in Males With Deleted in Germ Cells.

MGAT1 and complex N-glycans are required for spermatogenesis and fertility. Conditional deletion of in spermatogonia ( cKO) causes reduced ERK1/2 signaling and the formation of multinucleated germ cells (MNC). Here we show that glycomics analysis of N-glycans released from fixed testis sections and analyzed by MALDI imaging mass spectrometry (MALDI-IMS) revealed a loss of MGAT1 activity in all germ cells based on the accumulation of the oligomannosyl substrate of MGAT1. To determine in which type of germ cell MGAT1 is essential for spermatogenesis, we generated cKO males that also expressed a transgene under the control of a germ cell-specific promoter - for spermatogonia, for spermatocytes and for spermatids. Males expressing each transgene were fertile, and both males and females transmitted each transgene. When --HA was expressed in cKO males, spermatogenesis was rescued based on the morphology of testis sections, the complement of N-glycans on basigin, lectin histochemistry, MALDI-IMS, and fertility. By contrast, neither expressed in spermatocytes, nor the - transgene expressed in spermatids rescued spermatogenesis or fertility in cKO males. Therefore, MGAT1 must be expressed in spermatogonia for spermatogenesis to proceed normally.