School of BioSciences - Research Publications

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Author: FENELON, JANE × Author: Fenelon, Jane × Author: Renfree, Marilyn × Author: Shaw, Geoffrey × Start date: 2004 × Type: Journal Article ×

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    A new role for muscle segment homeobox genes in mammalian embryonic diapause
    Cha, J ; Sun, X ; Bartos, A ; Fenelon, J ; Lefevre, P ; Daikoku, T ; Shaw, G ; Maxson, R ; Murphy, BD ; Renfree, MB ; Dey, SK (ROYAL SOC, 2013-04)
    Mammalian embryonic diapause is a phenomenon defined by the temporary arrest in blastocyst growth and metabolic activity within the uterus which synchronously becomes quiescent to blastocyst activation and implantation. This reproductive strategy temporally uncouples conception from parturition until environmental or maternal conditions are favourable for the survival of the mother and newborn. The underlying molecular mechanism by which the uterus and embryo temporarily achieve quiescence, maintain blastocyst survival and then resume blastocyst activation with subsequent implantation remains unknown. Here, we show that uterine expression of Msx1 or Msx2, members of an ancient, highly conserved homeobox gene family, persists in three unrelated mammalian species during diapause, followed by rapid downregulation with blastocyst activation and implantation. Mice with uterine inactivation of Msx1 and Msx2 fail to achieve diapause and reactivation. Remarkably, the North American mink and Australian tammar wallaby share similar expression patterns of MSX1 or MSX2 as in mice-it persists during diapause and is rapidly downregulated upon blastocyst activation and implantation. Evidence from mouse studies suggests that the effects of Msx genes in diapause are mediated through Wnt5a, a known transcriptional target of uterine Msx. These studies provide strong evidence that the Msx gene family constitutes a common conserved molecular mediator in the uterus during embryonic diapause to improve female reproductive fitness.
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    A novel MSMB-related microprotein in the postovulatory egg coats of marsupials
    Frankenberg, S ; Fenelon, J ; Dopheide, B ; Shaw, G ; Renfree, MB (BMC, 2011-12-30)
    BACKGROUND: Early marsupial conceptuses differ markedly from those of eutherian mammals, especially during cleavage and early blastocyst stages of development. Additionally, in marsupials the zona pellucida is surrounded by two acellular layers, the mucoid coat and shell, which are formed from secretions from the reproductive tract. RESULTS: We report the identification of a novel postovulatory coat component in marsupials, which we call uterinesecreted microprotein (USM). USM belongs to a family of disulfide-rich microproteins of unconfirmed function that is found throughout deuterostomes and in some protostomes, and includes β-microseminoprotein (MSMB) and prostate-associated microseminoprotein (MSMP). We describe the evolution of this family in detail, including USM-related sequences in other vertebrates. The orthologue of USM in the tammar wallaby, USM1, is expressed by the endometrium with a dynamic temporal profile, possibly under the control of progesterone. CONCLUSIONS: USM appears to have evolved in a mammalian ancestor specifically as a component of the postovulatory coats. By analogy with the known properties of MSMB, it may have roles in regulating sperm motility/survival or in the immune system. However, its C-terminal domain is greatly truncated compared with MSMB, suggesting a divergent function.