TY - JOUR
T1 - The NOBOX protein becomes undetectable in developmentally competent antral and ovulated oocytes
AU - Belli, Martina
AU - Cimadomo, Danilo
AU - Merico, Valeria
AU - Redi, Carlo A.
AU - Garagna, Silvia
AU - Zuccotti, Maurizio
PY - 2013
Y1 - 2013
N2 - The oocyte-specific NOBOX protein is an important player during oocyte growth. Its absence in Nobox-/- mice arrests the transition from primordial to growing follicles and down-regulates the expression of a number of genes, including Oct4, a transcription factor crucial in the acquisition of oocyte developmental competence. Despite its role during folliculogenesis, a clear description of the expression of NOBOX throughout oocyte growth is lacking. Here, we have analysed the pattern of expression of both the Nobox gene (qRT-PCR) and its protein (immunofluorescence) during folliculogenesis, classifying the oocytes based on their size (six classes: 10-30, 31-40, 41-50, 51-60, 61-70, 71-80 μm) and chromatin organisation (NSN, Non Surrounded Nucleolus or SN, Surrounded Nucleolus). Significant differences were observed in Nobox transcription in the group of 41-50 μm (NSN > SN), 71-80 μm (NSN > SN) and in developmentally incompetent metaphase II-derived NSN (MIINSN) or competent metaphase II-derived SN (MIISN) oocytes (MIINSN > MIISN). The NOBOX protein is expressed throughout oocyte growth in the nucleus of ovarian NSN and in MIINSN oocytes; in contrast, beginning with SN oocytes of 61-70 μm, it becomes almost undetectable. Our data, while being in line with the hypothesis of a regulative role of NOBOX on Oct4 gene expression at the primordial/primary stage, when both transcription factors are coincidentally expressed, also indicate that this role might not be maintained in the subsequent growing stages. Furthermore, the sharp difference of NOBOX expression in developmentally incompetent or competent oocytes makes this protein a putative marker of their quality.
AB - The oocyte-specific NOBOX protein is an important player during oocyte growth. Its absence in Nobox-/- mice arrests the transition from primordial to growing follicles and down-regulates the expression of a number of genes, including Oct4, a transcription factor crucial in the acquisition of oocyte developmental competence. Despite its role during folliculogenesis, a clear description of the expression of NOBOX throughout oocyte growth is lacking. Here, we have analysed the pattern of expression of both the Nobox gene (qRT-PCR) and its protein (immunofluorescence) during folliculogenesis, classifying the oocytes based on their size (six classes: 10-30, 31-40, 41-50, 51-60, 61-70, 71-80 μm) and chromatin organisation (NSN, Non Surrounded Nucleolus or SN, Surrounded Nucleolus). Significant differences were observed in Nobox transcription in the group of 41-50 μm (NSN > SN), 71-80 μm (NSN > SN) and in developmentally incompetent metaphase II-derived NSN (MIINSN) or competent metaphase II-derived SN (MIISN) oocytes (MIINSN > MIISN). The NOBOX protein is expressed throughout oocyte growth in the nucleus of ovarian NSN and in MIINSN oocytes; in contrast, beginning with SN oocytes of 61-70 μm, it becomes almost undetectable. Our data, while being in line with the hypothesis of a regulative role of NOBOX on Oct4 gene expression at the primordial/primary stage, when both transcription factors are coincidentally expressed, also indicate that this role might not be maintained in the subsequent growing stages. Furthermore, the sharp difference of NOBOX expression in developmentally incompetent or competent oocytes makes this protein a putative marker of their quality.
KW - Folliculogenesis
KW - NOBOX
KW - Oocyte developmental competence
KW - Oocyte growth
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U2 - 10.1387/ijdb.120125mz
DO - 10.1387/ijdb.120125mz
M3 - Article
C2 - 23585350
AN - SCOPUS:84875183319
VL - 57
SP - 35
EP - 39
JO - International Journal of Developmental Biology
JF - International Journal of Developmental Biology
SN - 0214-6282
IS - 1
ER -