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Storage in the yolk platelets of low MW DNA produced by the regressing follicle cells
Author(s) -
Motta C.M.,
Tammaro S.,
Cicale A.,
Indolfi P.,
Iodice C.,
Spagnuolo M.S.,
Filosa S.
Publication year - 2001
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1049
Subject(s) - biology , vitellogenesis , follicle , yolk , oocyte , dna laddering , microbiology and biotechnology , ovarian follicle , oogenesis , dna , apoptosis , medicine , follicular phase , endocrinology , biochemistry , embryo , dna fragmentation , ecology , programmed cell death
The present work was carried out to clarify the nature and origin of the yolk DNA present in vitellogenic oocytes of the lizard Podarcis sicula. Morphological and biochemical evidences indicate that it has an intrafollicular origin, from the apoptotic bodies resulting from follicle cells regression at the end of previtellogenesis. This conclusion is reinforced by the observation that the oocyte membrane, in in vitro experiments, is unpermeable to exogenous DNA. Biochemical evidences reveal that the yolk DNA has a low (200bp) molecular weight and this suggests that it is produced by the endonucleases typically involved in apoptotic DNA laddering. Indeed, immunocytochemical analyses demonstrate that follicle cells contain significant amounts of DNAse I. In immunoblots, carried out during different periods of the ovarian cycle, the enzyme shows a MW of about 33, 66 or 100 kDa thus indicating that its activity in the follicle of Podarcis is modulated by dimerization and/or binding to regulatory factors. Mol. Reprod. Dev. 59: 422–430, 2001. © 2001 Wiley‐Liss, Inc.