MATER protein expression and intracellular localization throughout folliculogenesis and preimplantation embryo development in the bovine

• Main Authors: Mermillod Pascal, Delaleu Bernadette, Thélie Aurore, Uzbekova Svetlana, Perreau Christine, Pennetier Sophie, Dalbiès-Tran Rozenn
• Format: Article
• Language: English
• Published: BMC 2006-06-01
• Series: BMC Developmental Biology
• Online Access: http://www.biomedcentral.com/1471-213X/6/26

<p>Abstract</p> <p>Background</p> <p><it>Mater </it>(Maternal Antigen that Embryos Require), also known as <it>Nalp5</it> (NACHT, leucine rich repeat and PYD containing 5), is an oocyte-specific maternal effect gene required for early embryonic development beyond the two-cell stage in mouse. We previously characterized the bovine orthologue <it>MATER </it>as an oocyte marker gene in cattle, and this gene was recently assigned to a QTL region for reproductive traits.</p> <p>Results</p> <p>Here we have analyzed gene expression during folliculogenesis and preimplantation embryo development. <it>In situ </it>hybridization and immunohistochemistry on bovine ovarian section revealed that both the transcript and protein are restricted to the oocyte from primary follicles onwards, and accumulate in the oocyte cytoplasm during follicle growth. In immature oocytes, cytoplasmic, and more precisely cytosolic localization of MATER was confirmed by immunohistochemistry coupled with confocal microscopy and immunogold electron microscopy. By real-time PCR, MATER messenger RNA was observed to decrease strongly during maturation, and progressively during the embryo cleavage stages; it was hardly detected in morulae and blastocysts. The protein persisted after fertilization up until the blastocyst stage, and was mostly degraded after hatching. A similar predominantly cytoplasmic localization was observed in blastomeres from embryos up to 8-cells, with an apparent concentration near the nuclear membrane.</p> <p>Conclusion</p> <p>Altogether, these expression patterns are consistent with bovine MATER protein being an oocyte specific maternal effect factor as in mouse.</p>