GERM CELL-SPECIFIC DNA AND RNA-BINDING PROTEINS P48 52 ARE EXPRESSED AT SPECIFIC STAGES OF MALE GERM-CELL DEVELOPMENT AND ARE PRESENT IN THE CHROMATOID BODY/
R. Oko et al., GERM CELL-SPECIFIC DNA AND RNA-BINDING PROTEINS P48 52 ARE EXPRESSED AT SPECIFIC STAGES OF MALE GERM-CELL DEVELOPMENT AND ARE PRESENT IN THE CHROMATOID BODY/, Molecular reproduction and development, 44(1), 1996, pp. 1-13
Proteins homologous to the Xenopus oocyte mRNA binding proteins mRNP(3
+4) and designated p48/52 have been identified in male mouse germ cell
s (1993: Dev Biol 158:90-100). Western and Northwestern blots of extra
cts from testes and isolated germ cells indicate that p48/52 are prese
nt during meiosis but reach their highest levels postmeiotically at a
time when many mRNAs are stored. Here we analyze the cellular and subc
ellular distribution of p48/52 in rat and mouse testes by LM and EM im
munocytochemistry using an anti-mRNP(3+4) antibody. Immunolabeling was
found to be predominantly cytoplasmic and specific to germ cells at c
ertain periods during their development. p48/52 were first detected in
early pachytene spermatocytes at stage V of the seminiferous cycle an
d progressively increased during the remainder of meiotic prophase to
a post-meiotic peak in steps 1-8 round spermatids; thereafter, labelin
g gradually declined as elongated spermatids underwent nuclear condens
ation and elongation. A proportionally higher concentration of cytopla
smic immunolabeling was found within the lacunae of the anastomotic gr
anulofilamentous network of the chromatoid body. The pattern of synthe
sis of these mRNA binding proteins together with their association wit
h the chromatoid body suggests a role as germ cell-specific mRNA stabi
lizing and/or storage proteins. (C) 1996 Wiley-Liss, Inc.