|
|
|
|
|
|
|
||
* Department of Molecular Genetics and Cell Biology, Basonuclin is a zinc finger protein that was
thought to be restricted to keratinocytes of stratified
squamous epithelia. In epidermis, basonuclin is associated with the nuclei of mitotically active basal cells but
not in terminally differentiating keratinocytes. We report here the isolation of a novel form of basonuclin,
which we show is also expressed in stratified epithelia.
Most unexpectedly, we find both forms in testis, where
a surprising localization pattern was uncovered. While
basonuclin RNA expression occurs in mitotically active
germ cells, protein was not detected until the meiotic
stage, where basonuclin localized to the appendage of
the distal centriole of spermatocytes and spermatids.
Near the end of spermiogenesis, basonuclin also accumulated in the acrosome and mitochondrial sheath surrounding the flagellum. Intriguingly, a perfect six-
amino acid residue mitochondrial targeting sequence (Komiya, T., N. Hachiya, M. Sakaguchi, T. Omura, and
K. Mihara. 1994. J. Biol. Chem. 269:30893-30897;
Shore, G.C., H.M. McBride, D.G. Millar, N.A.
Steenaart, and M. Nguyen. 1995. Eur. J. Biochem. 227:
9-18; McBride, H.M., I.S. Goping, and G.C. Shore.
1996. J. Cell. Biol. 134:307-313) is present in basonuclin
1a but not in the 1b form. Moreover, three distinct affinity-purified peptide antibodies gave this unusual pattern of basonuclin antibody staining, which was confirmed by cell fractionation studies. Our findings suggest a unique role for basonuclin in centrosomes
within the developing spermatid, and a role for one of
the protein forms in germ cell mitochondrial function.
Its localization with the acrosome suggests that it may
also perform a special function during or shortly after
fertilization.
Department of Biochemistry and Molecular Biology, The Howard
Hughes Medical Institute, The University of Chicago, Chicago, Illinois 60637
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
