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General Comment |
Bobe J, et al 2001 reported a Cysteine protease inhibitor that is specifically expressed in pre-
and early-vitellogenic oocytes from the brook trout
periovulatory ovary.
A cDNA fragment hybridizing with a transcript abundant in the periovulatory
ovary was obtained while performing subtractive cloning on brook trout
ovulatory and postovulatory ovarian tissue. Using this fragment as a probe, a
478 bp full-length cDNA was obtained by screening an ovulatory ovarian cDNA
library. This cDNA presumably codes for an 88 amino acid protein that is
structurally related to a new family of cysteine protease inhibitors
characterized by the presence of a type I thyroglobulin motif in the amino
acid sequence. Therefore, the protein was tentatively named an oocyte cysteine
protease inhibitor (OCPI). On Northern blots, the OCPI cDNA hybridizes with a
0.5 kb transcript present in the ovary during the periovulatory period. The
OCPI transcript and protein were localized to the cytoplasm of pre- and
early-vitellogenic oocytes. On Northern blots of RNA from other tissues, the
OCPI transcript was detected only in the ovary, On Western blots, OCPI was
detected in the ovarian tissue at all periovulatory stages tested. The
specific localization of both OCPI transcript and protein to pre- and
early-vitellogenic oocytes and the structural similarity to protease
inhibitors, suggest that OCPI might be involved in the protection of oocytes
during the periovulatory period or in the regulation of yolk formation and
degradation.
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