HSP70-2 is part of the synaptonemal complex in mouse and hamster spermatocytes.
Mouse spermatogenic cells are known to express HSP70-2, a member of the HSP70 family of heat-shock proteins. The purpose of the present study was to characterize further the expression and localization of HSP70-2 in meiotic cells of mice and hamsters. After separating mouse spermatogenic cells into cytoplasmic and nuclear fractions, proteins were separated by two-dimensional gel electrophoresis and detected with HSP-specific antibodies. Of several HSP70 proteins identified in the cytoplasm, only HSC70 and HSP70-2 were also detected in the nucleus. Immunocytological analyses of spermatocyte prophase cells revealed that HSP70-2 was associated with the synaptonemal complex. Surface-spread synaptonemal complexes at pachytene and diplotene stages labeled distinctly with the antiserum to HSP70-2. Synaptonemal complexes from fetal mouse oocytes failed to show any evidence of HSP70-2. Reverse-transcriptase-polymerase chain reaction (RT-PCR) analyses of gene expression confirmed this sex specificity; Hsp70-2 mRNA was detected in mouse testes, but not ovaries. These findings are suggestive of a previously unsuspected sexual dimorphism in structure and/or function of the synaptonemal complex.
Allen
J W
JW
National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
Dix
D J
DJ
Collins
B W
BW
Merrick
B A
BA
He
C
C
Selkirk
J K
JK
Poorman-Allen
P
P
Dresser
M E
ME
Eddy
E M
EM
D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000737:chemistry; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis*; D007106:Immune Sera; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry; D016133:Polymerase Chain Reaction / Q000379:methods; D013090:Spermatocytes / Q000737:chemistry / Q000166:cytology*; D013573:Synaptonemal Complex / Q000502:physiology*
D018840:HSP70 Heat-Shock Proteins; D007106:Immune Sera