Molecular mechanisms regulating bovine ovarian follicular selection

Authors

  • Zhilin Liu,

    1. Division of Animal Sciences, University of Missouri-Columbia, Columbia, Missouri
    Current affiliation:
    1. Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston Texas 77030.
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  • Robert S. Youngquist,

    1. Veterinary Medicine and Surgery, University of Missouri-Columbia, Columbia, Missouri
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  • H. Allen Garverick,

    1. Division of Animal Sciences, University of Missouri-Columbia, Columbia, Missouri
    Current affiliation:
    1. Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston Texas 77030.
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  • Eric Antoniou

    Corresponding author
    1. Division of Animal Sciences, University of Missouri-Columbia, Columbia, Missouri
    Current affiliation:
    1. Jackson Laboratory Gene Expression Laboratory, 600 Main Street, Bar Harbor, Maine 04609.
    • Division of Animal Sciences, University of Missouri-Columbia, 920 East Campus Drive Columbia MO 65211.
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Abstract

Transcription profiling of ovarian follicles. Understanding the mechanisms by which a single follicle is selected for further ovulation is important to control fertility in mammals. However, development of new treatments is limited by our poor understanding of molecular mechanisms regulating follicular selection. Our hypothesis is that genes involved in the control of cell proliferation and apoptosis are differentially regulated during follicular selection. Our objective was to identify these new genes. Bovine follicles were collected and gene expression levels were measured using microarrays. First, follicles were allocated to three groups, according to the time spent from the initiation of follicular wave to surgery (24 H, 36 H, and 48–60 H). Fifty-seven genes are differentially expressed at a false discovery rate of 5%. These genes are involved in the control of lipid metabolism (P-value = 0.0005), cell proliferation (0.007), cell death (0.003), cell morphology (0.003), and immune response (0.003). Follicles were also grouped into four categories, according to the expected time of deviation (early deviation; 8 mm, mid-deviation; 8.5 mm, late deviation; 9 mm, dominant follicles; ≥10 mm). One hundred and twenty eight genes are differentially expressed between these four groups, including genes involved in cell proliferation (0.00002), cell death (0.0006), cell-to-cell signaling (0.003), cell morphology (0.003), lipid metabolism (0.0004), and immune response (0.00007). The expression levels of 10 genes were confirmed using quantitative real time PCR. As expected, we identified new differentially regulated genes involved in the control of cell growth and apoptosis. We also discovered a potential role for immune cells, and in particular macrophages, in follicular selection. Mol. Reprod. Dev. 76: 351–366, 2009. © 2008 Wiley-Liss, Inc.

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