Ma. Russo et al., LOW-AFFINITY NERVE GROWTH-FACTOR RECEPTOR IS EXPRESSED DURING TESTICULAR MORPHOGENESIS AND IN GERM-CELLS AT SPECIFIC STAGES OF SPERMATOGENESIS, Molecular reproduction and development, 37(2), 1994, pp. 157-166
Nerve growth factor (NGF) is essential for neuronal development and di
fferentiation. Recent reports have shown that its low-affinity recepto
r (LNGFR) is expressed and developmentally regulated in a broad range
of embryonic and adult tissues outside the nervous system, although th
e functions of the receptor in such tissues remain unknown. Recently,
NGF and LNGFR have been detected in adult mouse, rat, and human testis
. The results of the present work demonstrate that LNGFR is expressed
much before the onset of spermatogenesis in both mouse and rat testis.
In situ hybridization shows that the mRNA for LNGFR is expressed in t
he peritubular cells of the embryonic mouse testis. Immunohistochemica
l analysis of the rat testis shows LNGFR-expressing cells to be scatte
red in the intertubular compartment in the embryonic testis, and to be
come organized in a cellular layer that surrounds myoid cells of the s
eminiferous tubules during postnatal development. Furthermore, in peri
-puberal and adult mouse and rat testis we have identified the express
ion of an abundant and shorter mRNA of 3.2 kb that cross hybridizes to
the low-affinity NGF receptor transcript (3.7 kb). This shorter mRNA
species, which appears at the beginning of spermatogenesis in the adul
t, has been identified by in situ hybridization and by Northern blot w
ith RNA isolated from homogeneous populations of meiotic germ cells to
be expressed by pachytene spermatocytes and round spermatids. Our res
ults suggest a complex developmental role for LNGFR during testicular
morphogenesis and identify the expression, at specific stages of sperm
atogenesis, of a new germ cell-specific transcript homologous to the r
eceptor RNA. (C) 1994 Wiley-Liss, Inc.