title: Flow cytometric analysis of FSHR, BMRR1B, LHR and apoptosis in granulosa cells and ovulation rate in merino sheep.
abstract: The aim of the present study was to determine the direct cause of the mutation-induced, increased ovulation rate in Booroola Merino (BB) sheep. Granulosa cells were removed from antral follicles before ovulation and post-ovulation from BB (n=5) and WT (n=12) Merino ewes. Direct immunofluorescence measurement of mature cell surface receptors using flow cytometry demonstrated a significant up-regulation of FSH receptor (FSHR), transforming growth factor beta type 1, bone morphogenetic protein receptor (BMPR1B), and LH receptor (LHR) in BB sheep. The increased density of FSHR and LHR provide novel evidence of a mechanism for increasing the number of follicles that are recruited during dominant follicle selection. The compounding increase in receptors with increasing follicle size maintained the multiple follicles and reduced the apoptosis, which contributed to a high ovulation rate in BB sheep. In addition, we report a mutation-independent mechanism of down-regulation to reduce receptor density of the leading dominant follicle in sheep. The suppression of receptor density coincides with the cessation of mitogenic growth and steroidogenic differentiation as part of the luteinization of the follicle. The BB mutation-induced attenuation of BMPR1B signaling led to an increased density of the FSHR and LHR and a concurrent reduction in apoptosis to increase the ovulation rate. The role of BMPs in receptor modulation is implicated in the development of multiple ovulations.
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia sheenaregan@aapt.net.au.
authors.forename: Sheena L P
authors.initials: SL
authors.lastname: Regan
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia.
authors.forename: James R
authors.initials: JR
authors.lastname: McFarlane
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia.
authors.forename: Tim
authors.initials: T
authors.lastname: O'Shea
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Andronicos
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia.
authors.forename: Frank
authors.initials: F
authors.lastname: Arfuso
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia.
authors.forename: Arun
authors.initials: A
authors.lastname: Dharmarajan
authors.affiliation: School of Biomedical SciencesCurtin Health Innovation Research Institute, Curtin University, GPO Box U1987, Perth, Western Australia 6845, AustraliaCentre of Bioactive Discovery in Health and AgeingUniversity of New England, Armidale, New South Wales, Australia.
authors.forename: Ghanim
authors.initials: G
authors.lastname: Almahbobi
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006107:Granulosa Cells / Q000187:drug effects*; D009154:Mutation / Q000235:genetics / Q000502:physiology; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000502:physiology; D010060:Ovulation / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D011247:Pregnancy; D011962:Receptors, FSH / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D011974:Receptors, LH / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D034561:Sheep, Domestic; D013256:Steroids / Q000096:biosynthesis
chemical_list: D011962:Receptors, FSH; D011974:Receptors, LH; D013256:Steroids; D052005:Bone Morphogenetic Protein Receptors, Type I