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Differential regulation of abundance and deadenylation of maternal transcripts during bovine oocyte maturation in vitro and in vivo.

Thélie A, Papillier P, Pennetier S, Perreau C, Traverso JM, Uzbekova S, Mermillod P, Joly C, Humblot P, Dalbiès-Tran R - BMC Dev. Biol. (2007)

Bottom Line: Throughout in vitro development, oocyte restricted transcripts were progressively degraded until the morula stage, except for MELK ; and the corresponding genes remained silent after major embryonic genome activation.Altogether, our data emphasize the extent of post-transcriptional regulation during oocyte maturation.They do not evidence a general alteration of this phenomenon after in vitro maturation as compared to in vivo maturation, but indicate that some individual messenger RNA can be affected.

View Article: PubMed Central - HTML - PubMed

Affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France. Aurore.Thelie@tours.inra.fr

ABSTRACT

Background: In bovine maturing oocytes and cleavage stage embryos, gene expression is mostly controlled at the post-transcriptional level, through degradation and deadenylation/polyadenylation. We have investigated how post transcriptional control of maternal transcripts was affected during in vitro and in vivo maturation, as a model of differential developmental competence.

Results: Using real time PCR, we have analyzed variation of maternal transcripts, in terms of abundance and polyadenylation, during in vitro or in vivo oocyte maturation and in vitro embryo development. Four genes are characterized here for the first time in bovine: ring finger protein 18 (RNF18) and breast cancer anti-estrogen resistance 4 (BCAR4), whose oocyte preferential expression was not previously reported in any species, as well as Maternal embryonic leucine zipper kinase (MELK) and STELLA. We included three known oocyte marker genes (Maternal antigen that embryos require (MATER), Zygote arrest 1 (ZAR1), NACHT, leucine rich repeat and PYD containing 9 (NALP9)). In addition, we selected transcripts previously identified as differentially regulated during maturation, peroxiredoxin 1 and 2 (PRDX1, PRDX2), inhibitor of DNA binding 2 and 3 (ID2, ID3), cyclin B1 (CCNB1), cell division cycle 2 (CDC2), as well as Aurora A (AURKA). Most transcripts underwent a moderate degradation during maturation. But they displayed sharply contrasted deadenylation patterns that account for variations observed previously by DNA array and correlated with the presence of a putative cytoplasmic polyadenylation element in their 3' untranslated region. Similar variations in abundance and polyadenylation status were observed during in vitro maturation or in vivo maturation, except for PRDX1, that appears as a marker of in vivo maturation. Throughout in vitro development, oocyte restricted transcripts were progressively degraded until the morula stage, except for MELK ; and the corresponding genes remained silent after major embryonic genome activation.

Conclusion: Altogether, our data emphasize the extent of post-transcriptional regulation during oocyte maturation. They do not evidence a general alteration of this phenomenon after in vitro maturation as compared to in vivo maturation, but indicate that some individual messenger RNA can be affected.

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Variation of maternal transcripts during in vitro and in vivo maturation. Variation of transcripts total forms (dark color bars) or polyadenylated forms (light color bars) during in vitro (blue) or in vivo (red) oocyte maturation. The ratio to the mean value in immature oocytes is represented (mean ± SEM). IO and MO refer to immature oocytes and mature oocytes respectively. For each gene and form, different letters indicate a significant difference between IO and MO; an asterisk indicates a significant difference between variation of total and polyadenylated forms; "≠" indicates a significant difference between in vitro and in vivo maturation (P < 0.05).
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Figure 2: Variation of maternal transcripts during in vitro and in vivo maturation. Variation of transcripts total forms (dark color bars) or polyadenylated forms (light color bars) during in vitro (blue) or in vivo (red) oocyte maturation. The ratio to the mean value in immature oocytes is represented (mean ± SEM). IO and MO refer to immature oocytes and mature oocytes respectively. For each gene and form, different letters indicate a significant difference between IO and MO; an asterisk indicates a significant difference between variation of total and polyadenylated forms; "≠" indicates a significant difference between in vitro and in vivo maturation (P < 0.05).

Mentions: We followed the variation of selected maternal transcripts during in vitro oocyte maturation, in terms of abundance and polyadenylation. Real-time PCR was run onto random hexamer-primed RT products, in order to estimate their abundance, and oligo(dT)15-primed RT products, which are affected by both abundance and polyadenylation. For each transcript, the ratio to the mean value in immature oocytes is represented (Fig 2). For most transcripts, including 18S ribosomal RNA, the abundance did not vary significant during maturation, although an average 20% decrease was observed. PRDX1, ID2 and MATER transcripts appeared the most affected (over 33% degraded). As expected due to transcription repression during maturation, no transcript displayed a significant increase. The patterns of polyadenylated transcripts revealed sharp contrasts. CDC2, PRDX1, PRDX2, ID2, MATER, ZAR1 transcripts were strongly affected, as detection level dropped below one third of their initial level. For all these genes, variations of the total and polyadenylated forms were significantly different during maturation (Fig. 2, *). For NALP9 and BCAR4 variant 1, the decrease (41 and 49% respectively) was still more important than the decline observed for the total form (27 and 23%), but the difference was not statistically significant. On the other hand, seven genes appeared hardly affected; the polyadenylated transcript followed a parallel evolution as the total form, and decreased by less than 30%. These were AURKA, CCNB1, ID3, MELK, RNF18, STELLA (two variants analyzed individually), and BCAR4 (both variants analyzed together).


Differential regulation of abundance and deadenylation of maternal transcripts during bovine oocyte maturation in vitro and in vivo.

Thélie A, Papillier P, Pennetier S, Perreau C, Traverso JM, Uzbekova S, Mermillod P, Joly C, Humblot P, Dalbiès-Tran R - BMC Dev. Biol. (2007)

Variation of maternal transcripts during in vitro and in vivo maturation. Variation of transcripts total forms (dark color bars) or polyadenylated forms (light color bars) during in vitro (blue) or in vivo (red) oocyte maturation. The ratio to the mean value in immature oocytes is represented (mean ± SEM). IO and MO refer to immature oocytes and mature oocytes respectively. For each gene and form, different letters indicate a significant difference between IO and MO; an asterisk indicates a significant difference between variation of total and polyadenylated forms; "≠" indicates a significant difference between in vitro and in vivo maturation (P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2211488&req=5

Figure 2: Variation of maternal transcripts during in vitro and in vivo maturation. Variation of transcripts total forms (dark color bars) or polyadenylated forms (light color bars) during in vitro (blue) or in vivo (red) oocyte maturation. The ratio to the mean value in immature oocytes is represented (mean ± SEM). IO and MO refer to immature oocytes and mature oocytes respectively. For each gene and form, different letters indicate a significant difference between IO and MO; an asterisk indicates a significant difference between variation of total and polyadenylated forms; "≠" indicates a significant difference between in vitro and in vivo maturation (P < 0.05).
Mentions: We followed the variation of selected maternal transcripts during in vitro oocyte maturation, in terms of abundance and polyadenylation. Real-time PCR was run onto random hexamer-primed RT products, in order to estimate their abundance, and oligo(dT)15-primed RT products, which are affected by both abundance and polyadenylation. For each transcript, the ratio to the mean value in immature oocytes is represented (Fig 2). For most transcripts, including 18S ribosomal RNA, the abundance did not vary significant during maturation, although an average 20% decrease was observed. PRDX1, ID2 and MATER transcripts appeared the most affected (over 33% degraded). As expected due to transcription repression during maturation, no transcript displayed a significant increase. The patterns of polyadenylated transcripts revealed sharp contrasts. CDC2, PRDX1, PRDX2, ID2, MATER, ZAR1 transcripts were strongly affected, as detection level dropped below one third of their initial level. For all these genes, variations of the total and polyadenylated forms were significantly different during maturation (Fig. 2, *). For NALP9 and BCAR4 variant 1, the decrease (41 and 49% respectively) was still more important than the decline observed for the total form (27 and 23%), but the difference was not statistically significant. On the other hand, seven genes appeared hardly affected; the polyadenylated transcript followed a parallel evolution as the total form, and decreased by less than 30%. These were AURKA, CCNB1, ID3, MELK, RNF18, STELLA (two variants analyzed individually), and BCAR4 (both variants analyzed together).

Bottom Line: Throughout in vitro development, oocyte restricted transcripts were progressively degraded until the morula stage, except for MELK ; and the corresponding genes remained silent after major embryonic genome activation.Altogether, our data emphasize the extent of post-transcriptional regulation during oocyte maturation.They do not evidence a general alteration of this phenomenon after in vitro maturation as compared to in vivo maturation, but indicate that some individual messenger RNA can be affected.

View Article: PubMed Central - HTML - PubMed

Affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France. Aurore.Thelie@tours.inra.fr

ABSTRACT

Background: In bovine maturing oocytes and cleavage stage embryos, gene expression is mostly controlled at the post-transcriptional level, through degradation and deadenylation/polyadenylation. We have investigated how post transcriptional control of maternal transcripts was affected during in vitro and in vivo maturation, as a model of differential developmental competence.

Results: Using real time PCR, we have analyzed variation of maternal transcripts, in terms of abundance and polyadenylation, during in vitro or in vivo oocyte maturation and in vitro embryo development. Four genes are characterized here for the first time in bovine: ring finger protein 18 (RNF18) and breast cancer anti-estrogen resistance 4 (BCAR4), whose oocyte preferential expression was not previously reported in any species, as well as Maternal embryonic leucine zipper kinase (MELK) and STELLA. We included three known oocyte marker genes (Maternal antigen that embryos require (MATER), Zygote arrest 1 (ZAR1), NACHT, leucine rich repeat and PYD containing 9 (NALP9)). In addition, we selected transcripts previously identified as differentially regulated during maturation, peroxiredoxin 1 and 2 (PRDX1, PRDX2), inhibitor of DNA binding 2 and 3 (ID2, ID3), cyclin B1 (CCNB1), cell division cycle 2 (CDC2), as well as Aurora A (AURKA). Most transcripts underwent a moderate degradation during maturation. But they displayed sharply contrasted deadenylation patterns that account for variations observed previously by DNA array and correlated with the presence of a putative cytoplasmic polyadenylation element in their 3' untranslated region. Similar variations in abundance and polyadenylation status were observed during in vitro maturation or in vivo maturation, except for PRDX1, that appears as a marker of in vivo maturation. Throughout in vitro development, oocyte restricted transcripts were progressively degraded until the morula stage, except for MELK ; and the corresponding genes remained silent after major embryonic genome activation.

Conclusion: Altogether, our data emphasize the extent of post-transcriptional regulation during oocyte maturation. They do not evidence a general alteration of this phenomenon after in vitro maturation as compared to in vivo maturation, but indicate that some individual messenger RNA can be affected.

Show MeSH
Related in: MedlinePlus