Project description:RNA-seq technology was used to identify differentially localized transcripts from Xenopus laevis and Xenopus tropicalis stage VI oocytes. Besides the discovery of a group of novel animally enriched RNAs, this study revealed a surprisingly low conservation of vegetal RNA localization between the two frog species. mRNA profiles of Xenopus laevis and Xenopus tropicalis animal and vegetal oocyte halves were generated by RNA-seq technology. For Xenopus laevis, animal and vegetal oocyte RNA preparations from two different females were generated in duplicates. For Xenopus tropicalis, animal and vegetal oocyte RNA preparations from two different females were analyzed.
Project description:RNA-seq technology was used to identify differentially localized transcripts from Xenopus laevis and Xenopus tropicalis stage VI oocytes. Besides the discovery of a group of novel animally enriched RNAs, this study revealed a surprisingly low conservation of vegetal RNA localization between the two frog species.
Project description:The molecular causes of deteriorating oocyte quality during aging are poorly defined. Since oocyte developmental competence relies on post-transcriptional regulations, we tested whether defective mRNA translation contributes to this decline in quality. Disruption in ribosome loading on maternal transcripts is present in old oocytes. Using a candidate approach, we detect altered translation of 3’-UTR-reporters and altered poly(A) length of the endogenous mRNAs. mRNA polyadenylation depends on the cytoplasmic polyadenylation binding protein 1 (CPEB1). Cpeb1 mRNA translation and protein levels are decreased in old oocytes. This decrease causes de-repression of Ccnb1 translation in quiescent oocytes, premature CDK1 activation, and accelerated reentry into meiosis. De-repression of Ccnb1 is corrected by Cpeb1 mRNA injection in old oocytes. Oocyte-specific Cpeb1 haploinsufficiency in young oocytes recapitulates all the translation phenotypes of old oocytes. These findings demonstrate that a dysfunction in the oocyte translation program is associated with the decline in oocyte quality during aging.
Project description:Characterization of mitochondria in non-growing oocytes from xenopus laevis compared to somatic controls of the following tissues: heart, liver and white adipose tissue.
Project description:The aim of this experiment was to investigate the binding profiles of the CPEB-family of RNA-binding proteins. To attain comparable results, all IPs were performed against the HA-tagged CPEBs.
Project description:We performed CPEB1 RIP-seq on freshly isolated muscle stem cells. We found that CPEB1 associated genes are enriched in translational regulation pathways.
Project description:To identify CPEB1 and CPEB4 regulated RNA we performed CPEB1 and CPEB4 RNA immunoprecipitation (RIP) followed by microarray hybridization analysis with striatal (St) RNA from wild-type (WT) and R6/1 mice (HD mice).
Project description:In vertebrates, sexual reproduction depends on the precisely temporally controlled translation of mRNAs stockpiled in the oocyte. The RNA-binding proteins Zar1 and Zar2 have been implicated in translational control in oocytes of several vertebrate species, but how they act mechanistically is still incompletely understood. Here, we investigate the function of Zar1l, a so far uncharacterized member of the Zar protein family, in Xenopus laevis oocytes. By combining biochemical assays and mass spectrometry, we reveal that Zar1l is a constituent of a known large ribonucleoparticle containing the translation repressor 4E-T and the central polyadenylation regulator CPEB1. Employing TRIM-Away, we show that depletion of Zar1l from prophase-I arrested oocytes results in premature meiotic maturation upon hormone treatment. We provide evidence that this is based on the precocious expression of the kinase cMos, a key promotor of meiotic resumption. Based on our data, we propose a model according to which degradation of Zar1l results in dissociation of 4E-T from CPEB1, thus weakening translation inhibition imposed by the mRNA 3’UTR of cMos and probably also other M-phase promoting regulators. Thus, our detailed characterization of the function of Zar1l reveals novel mechanistic insights into the regulation of maternal mRNA translation during vertebrate meiosis.