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Suppression Of Chemically Induced And Spontaneous Mouse Oocyte Activation By Amp-Activated Protein Kinase, Ru Ya, Stephen Downs
Suppression Of Chemically Induced And Spontaneous Mouse Oocyte Activation By Amp-Activated Protein Kinase, Ru Ya, Stephen Downs
Biological Sciences Faculty Research and Publications
Oocyte activation is an important process triggered by fertilization that initiates embryonic development. However, parthenogenetic activation can occur either spontaneously or with chemical treatments. The LT/Sv mouse strain is genetically predisposed to spontaneous activation. LT oocytes have a cell cycle defect and are ovulated at the metaphase I stage instead of metaphase II. A thorough understanding of the female meiosis defects in this strain remains elusive. We have reported that AMP-activated protein kinase (PRKA) has an important role in stimulating meiotic resumption and promoting completion of meiosis I while suppressing premature parthenogenetic activation. Here we show that early activation of …
Perturbing Microtubule Integrity Blocks Amp-Activated Protein Kinase-Induced Meiotic Resumption In Cultured Mouse Oocytes, Ru Ya, Stephen Downs
Perturbing Microtubule Integrity Blocks Amp-Activated Protein Kinase-Induced Meiotic Resumption In Cultured Mouse Oocytes, Ru Ya, Stephen Downs
Biological Sciences Faculty Research and Publications
The oocyte meiotic spindle is comprised of microtubules (MT) that bind chromatin and regulate both metaphase plate formation and karyokinesis during meiotic maturation; however, little information is known about their role in meiosis reinitiation. This study was conducted to determine if microtubule integrity is required for meiotic induction and to ascertain how it affects activation of AMP-activated protein kinase (AMPK), an important participant in the meiotic induction process. Treatment with microtubule-disrupting agents nocodazole and vinblastine suppressed meiotic resumption in a dose-dependent manner in both arrested cumulus cell-enclosed oocytes (CEO) stimulated with follicle-stimulating hormone (FSH) and arrested denuded oocytes (DO) stimulated …
Role Of Ampk Throughout Meiotic Maturation In The Mouse Oocyte: Evidence For Promotion Of Polar Body Formation And Suppression Of Premature Activation, Stephen Downs, Ru Ya, Christopher C. Davis
Role Of Ampk Throughout Meiotic Maturation In The Mouse Oocyte: Evidence For Promotion Of Polar Body Formation And Suppression Of Premature Activation, Stephen Downs, Ru Ya, Christopher C. Davis
Biological Sciences Faculty Research and Publications
This study was conducted to assess the role of AMPK in regulating meiosis in mouse oocytes from the germinal vesicle stage to metaphase II. Exposure of mouse cumulus cell-enclosed oocytes (CEO) and denuded oocytes (DO) during spontaneous maturation in vitro to AMPK-activating agents resulted in augmentation of the rate and frequency of polar body formation. Inhibitors of AMPK had an opposite, inhibitory effect. In addition, the AMPK inhibitor, compound C (Cmpd C) increased the frequency of oocyte activation. The stimulatory action of the AMPK-activating agent, AICAR, and the inhibitory action of Cmpd C were diminished if exposure was delayed, indicating …
The Mink Potassium Channel Exists In Functional And Nonfunctional Forms When Expressed In The Plasma Membrane Of Xenopus Oocytes, Edward M. Blumenthal, Leonard K. Kaczmarek
The Mink Potassium Channel Exists In Functional And Nonfunctional Forms When Expressed In The Plasma Membrane Of Xenopus Oocytes, Edward M. Blumenthal, Leonard K. Kaczmarek
Biological Sciences Faculty Research and Publications
The minK protein induces a slowly activating voltage-dependent potassium current when expressed in Xenopus oocytes. In order to measure the levels of minK protein in the plasma membrane, we have modified the minK gene by inserting a 9 amino acid epitope into the N- terminal domain of the protein sequence. When intact live oocytes are injected with the modified minK RNA and subsequently incubated with an antibody to this epitope, specific binding is detected, indicating that the N-terminal domain is extracellular. We found that when oocytes are injected with amounts of minK mRNA up to 50 ng, the levels of …