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Expression of maternally derived KHDC3, NLRP5, OOEP and TLE6 is associated with oocyte developmental competence in the ovine species.

Bebbere D, Ariu F, Bogliolo L, Masala L, Murrone O, Fattorini M, Falchi L, Ledda S - BMC Dev. Biol. (2014)

Bottom Line: Conversely, OOEP2 contains a premature termination codon, thus representing an alternative noncoding transcript and supporting the existence of aberrant splicing during ovine oogenesis.These findings confirm the existence of the SCMC in sheep and its key role for the oocyte developmental potential, deepening our understanding on the molecular differences underlying cytoplasmic vs nuclear maturation of the oocytes.Describing differences and overlaps in transcriptome composition between model organisms advance our comprehension of the diversity/uniformity between mammalian species during early embryonic development and provide information on genes that play important regulatory roles in fertility in nonmurine models, including the human.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. dbebbere@uniss.it.

ABSTRACT

Background: The sub-cortical maternal complex (SCMC), located in the subcortex of mouse oocytes and preimplantation embryos, is composed of at least four proteins encoded by maternal effect genes: OOEP, NLRP5/MATER, TLE6 and KHDC3/FILIA. The SCMC assembles during oocyte growth and was seen to be essential for murine zygote progression beyond the first embryonic cell divisions; although roles in chromatin reprogramming and embryonic genome activation were hypothesized, the full range of functions of the complex in preimplantation development remains largely unknown.

Results: Here we report the expression of the SCMC genes in ovine oocytes and pre-implantation embryos, describing for the first time its expression in a large mammalian species. We report sheep-specific patterns of expression and a relationship with the oocyte developmental potential in terms of delayed degradation of maternal SCMC transcripts in pre-implantation embryos derived from developmentally incompetent oocytes. In addition, by determining OOEP full length cDNA by Rapid Amplification of cDNA Ends (RACE) we identified two different transcript variants (OOEP1 and OOEP2), both expressed in oocytes and early embryos, but with different somatic tissue distributions. In silico translation showed that 140 aminoacid peptide OOEP1 shares an identity with orthologous proteins ranging from 95% with the bovine to 45% with mouse. Conversely, OOEP2 contains a premature termination codon, thus representing an alternative noncoding transcript and supporting the existence of aberrant splicing during ovine oogenesis.

Conclusions: These findings confirm the existence of the SCMC in sheep and its key role for the oocyte developmental potential, deepening our understanding on the molecular differences underlying cytoplasmic vs nuclear maturation of the oocytes. Describing differences and overlaps in transcriptome composition between model organisms advance our comprehension of the diversity/uniformity between mammalian species during early embryonic development and provide information on genes that play important regulatory roles in fertility in nonmurine models, including the human.

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Alignment of ovineOOEPtranscript variant I (cDNA: 679 bps) and variant II (cDNA: 860 bps) (spanning 1126 bps genomic DNA). Squares indicate exons: the filled parts indicate regions common to both transcripts, while open squares indicate non homologous segments. Dotted line indicate introns.
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Fig1: Alignment of ovineOOEPtranscript variant I (cDNA: 679 bps) and variant II (cDNA: 860 bps) (spanning 1126 bps genomic DNA). Squares indicate exons: the filled parts indicate regions common to both transcripts, while open squares indicate non homologous segments. Dotted line indicate introns.

Mentions: The full-length cDNA of OOEP was cloned by RACE technique in two fragments: the 5′ and the 3′. The amplification of the clones containing the 5′ fragment returned two products of different length (541 and 722 bps), while the amplification of the clones containing the 3′fragment returned one product of 227 bps. In summary, two transcript variants were isolated: one of 679 bps (OOEP1) and one of 860 bps (OOEP2) (Figure 1). The sequences were submitted to GenBank (http://www.ncbi.nlm.nih.gov/genbank/; accession numbers: KF218578 for OOEP1 and KF741040 for OOEP2).Figure 1


Expression of maternally derived KHDC3, NLRP5, OOEP and TLE6 is associated with oocyte developmental competence in the ovine species.

Bebbere D, Ariu F, Bogliolo L, Masala L, Murrone O, Fattorini M, Falchi L, Ledda S - BMC Dev. Biol. (2014)

Alignment of ovineOOEPtranscript variant I (cDNA: 679 bps) and variant II (cDNA: 860 bps) (spanning 1126 bps genomic DNA). Squares indicate exons: the filled parts indicate regions common to both transcripts, while open squares indicate non homologous segments. Dotted line indicate introns.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4247878&req=5

Fig1: Alignment of ovineOOEPtranscript variant I (cDNA: 679 bps) and variant II (cDNA: 860 bps) (spanning 1126 bps genomic DNA). Squares indicate exons: the filled parts indicate regions common to both transcripts, while open squares indicate non homologous segments. Dotted line indicate introns.
Mentions: The full-length cDNA of OOEP was cloned by RACE technique in two fragments: the 5′ and the 3′. The amplification of the clones containing the 5′ fragment returned two products of different length (541 and 722 bps), while the amplification of the clones containing the 3′fragment returned one product of 227 bps. In summary, two transcript variants were isolated: one of 679 bps (OOEP1) and one of 860 bps (OOEP2) (Figure 1). The sequences were submitted to GenBank (http://www.ncbi.nlm.nih.gov/genbank/; accession numbers: KF218578 for OOEP1 and KF741040 for OOEP2).Figure 1

Bottom Line: Conversely, OOEP2 contains a premature termination codon, thus representing an alternative noncoding transcript and supporting the existence of aberrant splicing during ovine oogenesis.These findings confirm the existence of the SCMC in sheep and its key role for the oocyte developmental potential, deepening our understanding on the molecular differences underlying cytoplasmic vs nuclear maturation of the oocytes.Describing differences and overlaps in transcriptome composition between model organisms advance our comprehension of the diversity/uniformity between mammalian species during early embryonic development and provide information on genes that play important regulatory roles in fertility in nonmurine models, including the human.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. dbebbere@uniss.it.

ABSTRACT

Background: The sub-cortical maternal complex (SCMC), located in the subcortex of mouse oocytes and preimplantation embryos, is composed of at least four proteins encoded by maternal effect genes: OOEP, NLRP5/MATER, TLE6 and KHDC3/FILIA. The SCMC assembles during oocyte growth and was seen to be essential for murine zygote progression beyond the first embryonic cell divisions; although roles in chromatin reprogramming and embryonic genome activation were hypothesized, the full range of functions of the complex in preimplantation development remains largely unknown.

Results: Here we report the expression of the SCMC genes in ovine oocytes and pre-implantation embryos, describing for the first time its expression in a large mammalian species. We report sheep-specific patterns of expression and a relationship with the oocyte developmental potential in terms of delayed degradation of maternal SCMC transcripts in pre-implantation embryos derived from developmentally incompetent oocytes. In addition, by determining OOEP full length cDNA by Rapid Amplification of cDNA Ends (RACE) we identified two different transcript variants (OOEP1 and OOEP2), both expressed in oocytes and early embryos, but with different somatic tissue distributions. In silico translation showed that 140 aminoacid peptide OOEP1 shares an identity with orthologous proteins ranging from 95% with the bovine to 45% with mouse. Conversely, OOEP2 contains a premature termination codon, thus representing an alternative noncoding transcript and supporting the existence of aberrant splicing during ovine oogenesis.

Conclusions: These findings confirm the existence of the SCMC in sheep and its key role for the oocyte developmental potential, deepening our understanding on the molecular differences underlying cytoplasmic vs nuclear maturation of the oocytes. Describing differences and overlaps in transcriptome composition between model organisms advance our comprehension of the diversity/uniformity between mammalian species during early embryonic development and provide information on genes that play important regulatory roles in fertility in nonmurine models, including the human.

Show MeSH
Related in: MedlinePlus