TY - JOUR
T1 - Nuclear localization of NORs and centromeres in mouse oocytes during folliculogenesis
AU - Longo, Frank
AU - Garagna, Silvia
AU - Merico, Valeria
AU - Orlandini, Guido
AU - Gatti, Rita
AU - Scandroglio, Renato
AU - Redi, Carlo Alberto
AU - Zuccotti, Maurizio
PY - 2003/11/1
Y1 - 2003/11/1
N2 - Mouse oocytes at the germinal vesicle stage are characterized by one of two nuclear morphologies: surrounded nucleolus (SN), in which the nucleolus is surrounded by a rim of Hoechst positive chromatin and not surrounded nucleolus (NSN), in which this rim is essentially absent. This morphological difference has a biological relevance as NSN oocytes are transcriptionally active, yet incapable of development beyond the two-cell stage. Whereas SN oocytes, which are transcriptionally inactive, are capable of development to the blastocyst stage. To further our understanding of the nuclear organization of the mouse oocyte during folliculogenesis, we have conducted a series of investigations employing silver methods that stain nucleolus organizer region (NOR), centromeres, and heterochromatin, as well as, specific antibodies for centromeres. Results obtained by a variety of microscopic methods (light, electron, immunochemical, and confocal) demonstrate: (1) a changing pattern of NOR staining during folliculogenesis that is specific to follicular type, and (2) significant differences in the organization of NORs and centromeres of isolated, antral NSN, and SN oocytes. These observations suggest possible means by which, chromosomes of mature, germinal vesicle oocytes are organized with respect to the nucleolus.
AB - Mouse oocytes at the germinal vesicle stage are characterized by one of two nuclear morphologies: surrounded nucleolus (SN), in which the nucleolus is surrounded by a rim of Hoechst positive chromatin and not surrounded nucleolus (NSN), in which this rim is essentially absent. This morphological difference has a biological relevance as NSN oocytes are transcriptionally active, yet incapable of development beyond the two-cell stage. Whereas SN oocytes, which are transcriptionally inactive, are capable of development to the blastocyst stage. To further our understanding of the nuclear organization of the mouse oocyte during folliculogenesis, we have conducted a series of investigations employing silver methods that stain nucleolus organizer region (NOR), centromeres, and heterochromatin, as well as, specific antibodies for centromeres. Results obtained by a variety of microscopic methods (light, electron, immunochemical, and confocal) demonstrate: (1) a changing pattern of NOR staining during folliculogenesis that is specific to follicular type, and (2) significant differences in the organization of NORs and centromeres of isolated, antral NSN, and SN oocytes. These observations suggest possible means by which, chromosomes of mature, germinal vesicle oocytes are organized with respect to the nucleolus.
KW - Heterochromatin
KW - Nucleolus
KW - Oogenesis
KW - rDNA
KW - Satellite DNA
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U2 - 10.1002/mrd.10354
DO - 10.1002/mrd.10354
M3 - Article
C2 - 14502607
AN - SCOPUS:0141593328
VL - 66
SP - 279
EP - 290
JO - Molecular Reproduction and Development
JF - Molecular Reproduction and Development
SN - 1040-452X
IS - 3
ER -