|
Comment |
RAB7 GTPase regulates actin dynamics for DRP1-mediated mitochondria function and spindle migration in mouse oocyte meiosis. Pan ZN et al. (2020) RAB7 is a small GTPase that belongs to the Rab family, and as a vesicle trafficking factor it is shown to regulate the transport to late endocytic compartments, autophagosome maturation and organelle function. In present study, we showed the critical roles of RAB7 GTPase on actin dynamics and mitochondria function in oocyte meiosis. RAB7 mainly accumulated at cortex and spindle periphery during oocyte maturation. RAB7 depletion caused the failure of polar body extrusion and asymmetric division, and Rab7 exogenous mRNA supplement could rescue the defects caused by RAB7 RNAi. Based on mass spectrometry analysis, we found that RAB7 associated with several actin nucleation factors and mitochondria-related proteins in oocytes. The depletion of RAB7 caused the decrease of actin dynamics, which further affected meiotic spindle migration to the oocyte cortex. In addition, we found that RAB7 could maintain mitochondrial membrane potential and the mitochondrial distribution in mouse oocytes, and this might be due to its effects on the phosphorylation of DRP1 at Ser616 domain. Taken together, our data indicated that RAB7 transported actin nucleation factor for actin polarization, which further affected the phosphorylation of DRP1 for mitochondria dynamics and the meiotic spindle migration in mouse oocytes.//////////////////
Differentially expressed genes and gene networks involved in pig ovarian follicular atresia. Terenina E et al. (2016) Ovarian folliculogenesis corresponds to the development of follicles leading to either ovulation or degeneration, this latter process being called atresia. Even if atresia involves apoptosis, its mechanism is not well-understood. The objective of this project was to analyse global gene expression in pig granulosa cells of ovarian follicles during atresia. The transcriptome analysis was performed using 9216 cDNAs microarray to identify gene networks and candidate genes involved in pig ovarian follicular atresia. One thousand six hundred and eighty four significantly regulated genes were differentially regulated between small healthy follicles and small atretic follicles. Among them, two hundred and eighty seven genes had a fold-change higher than 2 between the two follicle groups. Eleven genes (DKK3, GADD45A, CAMTA2, CCDC80, DAPK2, ECSIT, MSMB, NUPR1, RUNX2, SAMD4A, and ZNF628) having a fold-change higher than 5 between groups could likely serve as markers of follicular atresia. Moreover, automatic confrontation of deregulated genes with literature data enlightened 93 genes as regulatory candidates of pig granulosa cell atresia. Among these genes known to be inhibitors of apoptosis, stimulators of apoptosis or tumor suppressors INHBB, HNF4, CLU, different interleukins (IL5, IL24), TNF-associated receptor (TNFR1), and cytochrome-c oxidase (COX) were suggested as playing an important role in porcine atresia. Present study also enlists key upstream regulators in follicle atresia based on our results and on a literature review. The novel gene candidates and gene networks identified in the current study lead to a better understanding of the molecular regulation of ovarian follicular atresia.//////////////////
|