ABSTRACT
The Golgi apparatus of germ cells of the testis of adult rats was isolated and subjected to a proteomics analysis with 1318 proteins characterized and 20 localized in situ by light microscope immunocytochemistry. The data revealed unexpected temporal distributions of the 20 germ cell Golgi localized proteins from chaperones to protein-folding enzymes involved in protein maturation. Some proteins were selective for the Golgi apparatus of germ cells spanning the greater part of germ cell differentiation (spermatogenesis). Others were selective for spermatocytes and/or spermatids during acrosome formation. A segregation of two classes of Golgi proteins was also noted during acrosome formation, with some localizing to both the Golgi and acrosome, while others were restricted solely to the Golgi apparatus. Several Golgi markers defined the postacrosome Golgi migration. In addition, some proteins were expressed selectively during the last step of germ cell differentiation (i.e., step 19 spermatids) at a time when the Hermes body (cytoplasmic droplet) was being formed. In the case of the isolated Hermes body of epididymal sperm, 30 non-Golgi proteins were chosen from 1511 characterized by proteomics. These proteins were mapped according to the 14 stages of the cycle of the seminiferous epithelium, with a correlation being noted with specific germ cell organelles that may lead to an understanding of the functional significance of these proteins. In addition, the expression profile of the 30 non-Golgi proteins was compared to that of the 20 Golgi localized proteins according to the 14 stages of the cycle. In this way, similarities in waves of expression of these two different classes of proteins could be compared to reveal functional implications.
