https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:17021 Wed 11 Apr 2018 17:14:33 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27033 Xenopus and is expressed during ovarian development in Drosophila. In mammals Musashi is important for spermatogenesis and male fertility, but its role in the ovary has yet to be characterized. In this study we determined the expression of mammalian Musashi proteins MSI1 and MSI2 during mouse folliculogenesis, and through the use of a MSI2-specific knockout mouse model we identified that MSI2 is essential for normal follicle development. Time-course characterization of MSI1 and MSI2 revealed distinct differences in steady-state mRNA levels and protein expression/localization at important developmental time-points during folliculogenesis. Using a gene-trap mouse model that inactivates Msi2, we observed a significant decrease in ovarian mass, and change in follicle-stage composition due to developmental blocking of antral stage follicles and pre-antral follicle loss through atresia. We also confirmed that hormonally stimulated Msi2-deficient mice produce significantly fewer MII oocytes (60.9% less than controls, p < 0.05). Furthermore, the majority of these oocytes are of poor viability (62.2% non-viable/apoptotic, p < 0.05), which causes a reduction in female fertility evidenced by decreased litter size in Msi2-deficient animals (33.1% reduction to controls, p < 0.05). Our findings indicate that MSI1 and MSI2 display distinct expression profiles during mammalian folliculogenesis and that MSI2 is required for pre-antral follicle development.]]> Wed 11 Apr 2018 16:39:10 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:28064 Wed 11 Apr 2018 09:24:57 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46728 95% had at least 2 vaccine doses. Attack rates were 295 of 535 (55.1%) and 102 of 189 (54.0%), respectively (mean, 5 days postevent). At the ball, attack rates increased with time since vaccination: 12.5% among those vaccinated 1–2 months previously and 68.0% among those vaccinated ≥3 months previously; such differences were not found at the nightclub. Recent vaccination prevents Omicron infection, but is time and setting dependent, emphasizing the importance of nonpharmaceutical public health measures in addition to vaccine booster doses to maximize protection in high-risk contexts.]]> Tue 29 Nov 2022 11:55:33 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:9651 Sat 24 Mar 2018 08:35:26 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21158 FZR1 activity in the male germline led to both a mitotic and a meiotic testicular defect resulting in infertility due to the absence of mature spermatozoa. Spermatogonia in the prepubertal testes of such mice had abnormal proliferation and delayed entry into meiosis. Although early recombination events were initiated, male germ cells failed to progress beyond zygotene and underwent apoptosis. Loss of APC/C^FZR1 activity was associated with raised cyclin B1 levels, suggesting that CDK1 may trigger apoptosis. By contrast, female FZR1Δ mice were subfertile, with premature onset of ovarian failure by 5 months of age. Germ cell loss occurred embryonically in the ovary, around the time of the zygotene-pachytene transition, similar to that observed in males. In addition, the transition of primordial follicles into the growing follicle pool in the neonatal ovary was abnormal, such that the primordial follicles were prematurely depleted. We conclude that APC/C^FZR1 is an essential regulator of spermatogonial proliferation and early meiotic prophase I in both male and female germ cells and is therefore important in establishing the reproductive health of adult male and female mammals.]]> Sat 24 Mar 2018 08:00:18 AEDT ]]>