title: Immunoelectron microscopic study of BASP1 and MARCKS location in the early and late rat spermatids.
abstract: Immunoelectron microscopy was used to locate the proteins BASP1 and MARCKS in the post-meiotic spermatids of male rat testis. It was shown that in early spermatids, BASP1 and MARCKS accumulate in chromatoid bodies, which are characteristic organelles for these cells. During spermatogenesis, while the spermatid nucleus is still active, the chromatoid body periodically moves to the cell nucleus and absorbs the precursors of definite mRNAs and small RNAs. mRNAs are preserved in the chromatoid body until the corresponding proteins are needed, but their "fresh" mRNA cannot be formed due to the nucleus inactivation. The chromatoid body (0.5-1.5μm in diameter) has a cloud-like fibrous appearance with many fairly round cavities. In the chromatoid body, BASP1 and MARCKS are distributed mainly around the cavities and at periphery. Based on the known functions of BASP1 and MARCKS in neurons, it is conceivable that these proteins participate in non-random movements of the chromatoid body to the nucleus and in Ca(2+)-calmodulin enrichment. In late spermatids, BASP1 and MARCKS are located in the outer dense fiber layer belonging to a metabolically active spermatozoon region, the tail mid-piece. In spermatozoa, as in chromatoid body, BASP1 and MARCKS may bind Ca(2+)-calmodulin and therefore contribute to the activation of calcium-dependent biochemical processes.
authors.affiliation: Division of Molecular Biophysics, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Leningrad District, Russian Federation. m mosev@mail.ru
authors.forename: Mark I
authors.initials: MI
authors.lastname: Mosevitsky
authors.forename: Ekaterina S
authors.initials: ES
authors.lastname: Snigirevskaya
authors.forename: Yan Yu
authors.initials: YY
authors.lastname: Komissarchik
mesh_terms: D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000096:biosynthesis*; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D003598:Cytoskeletal Proteins / Q000096:biosynthesis*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D016253:Microscopy, Immunoelectron; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009685:Nuclear Envelope / Q000378:metabolism / Q000648:ultrastructure; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D013087:Spermatids / Q000378:metabolism* / Q000648:ultrastructure; D013091:Spermatogenesis; D013997:Time Factors
chemical_list: D002148:Calmodulin-Binding Proteins; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; C000619710:MARCKS protein, human; C000619712:Marcks protein, rat; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; C066853:Basp1 protein, rat