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Stage‐specific expression of phosphoprotein p19 during spermatogenesis in the rat
Author(s) -
Amat Jose A.,
Fields Kay L.,
Schubart Ulrich K.
Publication year - 1990
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080260414
Subject(s) - biology , phosphoprotein , meiosis , spermatogenesis , microbiology and biotechnology , p19 cell , somatic cell , western blot , endocrinology , cellular differentiation , phosphorylation , genetics , gene , adult stem cell
The expression of phosphoprotein p19, a 19‐kDa cytosolic substrate for cyclic adenosine monophosphate (cAMP)‐dependent protein kinase, occurs abundantly in brain and testis and is developmentally regulated. In the present study we have identified the cell types of adult rat testis that contain p19. Using cryostat sections, which were first incubated with rabbit anti‐p19 for immunohistochemistry followed by counterstaining with periodic acid‐Schiff (PAS)‐hematoxylin to reveal nuclear morphology, we demonstrate that immunoreactive p19 is detectable only in germ cells and is restricted to a limited stage of spermatogenesis. Expression first appears after the differentiating gametes have entered the prophase of meiosis, is abundant in spermatocytes until meiosis is completed, and declines to undetectable levels in maturing spermatids. We have ruled out immunocross‐reactivity with SCG10, a 22‐kDa protein that is closely related in structure to p19, by demonstrating, using Northern blot analysis, that RNA transcripts encoding SCG10 are not detectable in adult rat testis, whereas p19 is abundantly expressed. The transient expression of p19 during spermatogenesis suggests that the protein plays a role during male gamete differentiation.