A. Yagi et J. Paranko, EXTRACTIONS REVEAL SPECIFIC ARGENTOPHILIC PROTEINS IN RAT AND BULL SPERM HEADS, The Anatomical record, 239(2), 1994, pp. 126-136
Background: Silver-stainability (argentophilia) of cytoplasmic structu
res occurring in spermatids have been localized into the organizing pe
rinuclear theca, but the biochemical nature and structural association
s of these proteins with the cytoskeletal and membranous elements are
unresolved and, therefore, were the aim of the present study. Methods:
Light and electron microscopic analysis of the silver-stainability in
the rat spermatids and spermatozoa was carried out in the intact test
is tissue and epididymal spermatozoa and after their chemical and mech
anical extraction. Correlation of argentophilia with specific proteins
of rat and bovine spermatids and spermatozoa was investigated using a
recently developed technique for silver nitrate staining of proteins
on nitrocellulose. Results: Sequential formation of the silver-stainab
le domains seemed to proceed from the argentophilic acrosomal ring. Va
rious extractions indicated that argentophilia in the spermatids and s
permatozoa was mainly associated with the perinuclear theca and to som
e extent to the plasma membrane. Hyamine-soluble extract from spermato
zoa of rat and bull revealed only a single argentophilic protein of 13
0 kDa. Hyamine and SDS-soluble extracts of rat testis tissue contained
an additional group of argentophilic polypeptides of lower molecular
weight (115, 94, 36, 23, and 21 kDa). Conclusions: Reduction in the nu
mber of argentophilic proteins appears to be involved in a series of c
hanges in the cyto-architecture of developing spermatids. Tentative cy
toskeletal nature of argentophilic proteins remains to be identified.
Nevertheless, they may have important physical relations with the high
er-order organization of the sperm head cytoskeleton and overlying mem
branes. (C) 1994 Wiley-Liss, Inc.