title: Expression of maternally derived KHDC3, NLRP5, OOEP and TLE6 is associated with oocyte developmental competence in the ovine species.
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.
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. dbebbere@uniss.it.
authors.forename: Daniela
authors.initials: D
authors.lastname: Bebbere
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. federica@uniss.it.
authors.forename: Federica
authors.initials: F
authors.lastname: Ariu
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. luis@uniss.it.
authors.forename: Luisa
authors.initials: L
authors.lastname: Bogliolo
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. laumasala@uniss.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Masala
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. ombretta.murrone@gmail.com.
authors.forename: Ombretta
authors.initials: O
authors.lastname: Murrone
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. mfattorini@uniss.it.
authors.forename: Mauro
authors.initials: M
authors.lastname: Fattorini
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. lfalchi@uniss.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Falchi
authors.affiliation: Department of Veterinary Medicine, University of Sassari, via Vienna 2, 07100, Sassari, Italy. giodi@uniss.it.
authors.forename: Sergio
authors.initials: S
authors.lastname: Ledda
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000378:metabolism; D047108:Embryonic Development; D005260:Female; D005298:Fertility; D018507:Gene Expression Regulation, Developmental; D008297:Male; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D009928:Organ Specificity; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D034561:Sheep, Domestic / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome
chemical_list: D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014157:Transcription Factors