Stage-dependent changes in localization of a germ cell-specific lamin during mammalian spermatogenesis.
We had earlier identified a 110/120-kDa protein specific to nuclear matrix of rat pachytene spermatocytes (Behal, A., Prakash, K., and Rao, M.R.S. (1987) J. Biol. Chem. 262, 10898-10902). This protein is now shown to be a disulfide-linked homodimer of a 60-kDa polypeptide. Indirect immunofluorescence and Western blot analyses using anti-120-kDa polyclonal antibodies have shown that this protein is a component of the pore-complex lamina structure of spermatogonia. As germ cells enter meiotic prophase and the lamina structure disassembles, this polypeptide is redistributed in the nucleus and can be isolated as a component of synaptonemal complexes. Following meiotic division, this 60-kDa protein is relocalized in the lamina, then representing the sole major component of the lamina structure of round spermatids. The identity of the 60-kDa protein in the pore-complex lamina fraction and synaptonemal complexes was further confirmed by two-dimensional analysis of iodinated tryptic peptides. Such an analysis has also shown that the germ cell-specific 60-kDa protein is related but not identical to somatic lamin B.
Sudhakar
L
L
Department of Biochemistry, Center for Genetic Engineering, Indian Institute of Science, Bangalore.
Rao
M R
MR
D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D034921:Lamin Type B; D034882:Lamins; D008297:Male; D008970:Molecular Weight; D015530:Nuclear Matrix / Q000737:chemistry / Q000502:physiology*; D009687:Nuclear Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013090:Spermatocytes / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D013091:Spermatogenesis; D013094:Spermatozoa / Q000737:chemistry / Q000502:physiology*
D034921:Lamin Type B; D034882:Lamins; D009687:Nuclear Proteins