title: FTIR spectral signatures of mouse antral oocytes: molecular markers of oocyte maturation and developmental competence.
abstract: Mammalian antral oocytes with a Hoescht-positive DNA ring around the nucleolus (SN) are able to resume meiosis and to fully support the embryonic development, while oocytes with a non-surrounded nucleolus (NSN) cannot. Here, we applied FTIR microspectroscopy to characterize single SN and NSN mouse oocytes in order to try to elucidate some aspects of the mechanisms behind the different chromatin organization that impairs the full development of NSN oocyte-derived embryos. To this aim, oocytes were measured at three different stages of their maturation: just after isolation and classification as SN and NSN oocytes (time 0); after 10h of in vitro maturation, i.e. at the completion of the metaphase I (time 1); and after 20h of in vitro maturation, i.e. at the completion of the metaphase II (time 2). Significant spectral differences in the lipid (3050-2800cm(-1)) and protein (1700-1600cm(-1)) absorption regions were found between the two types of oocytes and among the different stages of maturation within the same oocyte type. Moreover, dramatic changes in nucleic acid content, concerning mainly the extent of transcription and polyadenylation, were detected in particular between 1000 and 800cm(-1). The use of the multivariate principal component-linear discriminant analysis (PCA-LDA) enabled us to identify the maturation stage in which the separation between the two types of oocytes took place, finding as the most discriminating wavenumbers those associated to transcriptional activity and polyadenylation, in agreement with the visual analysis of the spectral data.
authors: Fondazione IRCCS Policlinico San Matteo, V.le C. Golgi 19, Pavia, Italy.
authors: Diletta
authors: D
authors: Ami
authors: Paolo
authors: P
authors: Mereghetti
authors: Antonino
authors: A
authors: Natalello
authors: Silvia Maria
authors: SM
authors: Doglia
authors: Mario
authors: M
authors: Zanoni
authors: Carlo Alberto
authors: CA
authors: Redi
authors: Manuela
authors: M
authors: Monti
mesh_terms: D000818:Animals; D002466:Cell Nucleolus / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D016002:Discriminant Analysis; D005260:Female; D008055:Lipids / Q000032:analysis; D051379:Mice; D015999:Multivariate Analysis; D009865:Oocytes / Q000254:growth & development / Q000378:metabolism*; D006080:Ovarian Follicle / Q000166:cytology*; D025341:Principal Component Analysis; D011506:Proteins / Q000032:analysis; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013997:Time Factors
chemical_list: D008055:Lipids; D011506:Proteins; D004247:DNA