The number and quality of oocytes within the ovarian reserve largely determines fertility and reproductive lifespan in mammals. An oocytespecific transcription factor cascade controls oocyte development, and some of these transcription factors, such as newborn ovary homeobox gene (NOBOX), are candidate genes for primary ovarian insufficiency in women. Transcription factors are frequently modified by the posttranslational modification SUMOylation, but it is not known whether SUMOylation is required for function of the oocyte-specific transcription factors or if SUMOylation is required in oocytes during their development within the ovarian follicle. To test this, the sole E2 SUMO-conjugating enzyme, Ube2i, was ablated in mouse oocytes beginning in primordial follicles. Loss of oocyte Ube2i resulted in female infertility with major defects in stability of the primordial follicle pool, ovarian folliculogenesis, ovulation and meiosis. Transcriptomic profiling of ovaries suggests that loss of oocyte Ube2i caused defects in both oocyte-and granulosa cellexpressed genes, including NOBOX and some of its known target genes. Together, these studies show that SUMOylation is required in the mammalian oocyte during folliculogenesis for both oocyte development and communication with ovarian somatic cells.

Enteroviruses frequently result in respiratory and gastrointestinal illness; however, multiple subtypes, including poliovirus, can cause severe neurologic disease. Recent biennial increases (i.e., 2014, 2016, and 2018) in cases of non-polio acute flaccid paralysis have led to speculations that other enteroviruses, specifically enterovirus D68 (EV-D68), are emerging to fill the niche that was left from poliovirus eradication. A cluster of 11 suspect cases of pediatric acute flaccid myelitis (AFM) was identified in 2016 in Phoenix, AZ. Multiple genomic analyses identified the presence of EV-D68 in the majority of clinical AFM cases. Beyond limited detection of herpesvirus, no other likely etiologies were found in the cluster. These findings strengthen the likelihood that EV-D68 is a cause of AFM and show that the rapid molecular assays developed for this study are useful for investigations of AFM and EV-D68.

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Members of the differential screening-selected gene aberrative in neuroblastoma (DAN) protein family are developmentally conserved extracellular binding proteins that antagonize bone morphogenetic protein (BMP) signaling. This protein family includes the Gremlin proteins, GREM1 and GREM2, which have key functions during embryogenesis and adult physiology. While BMPs play essential roles in ovarian follicle development, the role of the DAN family in female reproductive physiology is less understood. We generated mice null for Grem2 to determine its role in female reproduction in addition to screening patients with primary ovarian insufficiency for variants in GREM2. Grem2−/− mice are viable, but female Grem2−/− mice have diminished fecundity and irregular estrous cycles. This is accompanied by significantly reduced production of ovarian anti-Müllerian hormone (AMH) from small growing follicles, leading to a significant decrease in serum AMH. Surprisingly, as AMH is a well-established marker of the ovarian reserve, morphometric analysis of ovarian follicles showed maintenance of primordial follicles in Grem2−/− mice like wild type littermates. While Grem2 mRNA transcripts were not detected in the pituitary, Grem2 is expressed in hypothalami of wild type female mice, suggesting the potential for dysfunction in multiple tissues composing the hypothalamic–pituitary-ovarian axis that contribute to the subfertility phenotype. Additionally, screening 106 women with primary ovarian insufficiency identified one individual with a heterozygous variant in GREM2 that lies within the predicted BMP-GREM2 interface. In total, these data suggest Grem2 is necessary for female fecundity by playing a novel role in regulating the HPO axis and contributing to female reproductive disease.

Members of the differential screening-selected gene aberrative in neuroblastoma (DAN) protein family are developmentally conserved extracellular binding proteins that antagonize bone morphogenetic protein (BMP) signaling. This protein family includes the Gremlin proteins, GREM1 and GREM2, which are known to have key functions during embryogenesis and adult physiology. While BMPs play essential roles in adult female reproductive physiology, the role of the DAN family in ovarian function is less understood. We generated mice null for Grem2 to study its role in female fertility in addition to screening patients with primary ovarian insufficiency for variants in GREM2. Grem2-/- mice are viable and female Grem2-/- mice have diminished fecundity and irregular estrous cycles. This is accompanied by reduced serum levels of anti-Müllerian hormone, a marker of the ovarian reserve, in adult mice. Alterations in ovarian expression of inhibin and activin subunit genes, which are required for regulation of the hypothalamic-pituitary-ovarian (HPO) axis, were identified. While Grem2 mRNA transcript was not detected in the pituitary, Grem2 was expressed in the hypothalami of wild type female mice. Additionally, screening 106 women with primary ovarian insufficiency identified one individual with a heterozygous variant in GREM2 that lies within the predicted BMP-GREM2 interface. In total, these data suggest that Grem2 is necessary for female fecundity by playing a novel role in regulating the HPO axis and possibly contributing to female reproductive disease.

SOHLH1 and NOBOX are oocyte‐expressed transcription factors with critical roles in ovary development and fertility. In mice, Sohlh1 and Nobox are essential for fertility through their regulation of the oocyte transcriptional network and cross‐talk to somatic cells. Sumoylation is a posttranslational modification that regulates transcription factor function, and we previously showed that mouse oocytes deficient for sumoylation had an altered transcriptional landscape that included significant changes in NOBOX target genes. Here, we show that mouse SOHLH1 is modified by SUMO2/3 at lysine 345 and mutation of this residue alters SOHLH1 nuclear to cytoplasmic localization. In NOBOX, we identify a non‐consensus SUMO site, K97, that eliminates NOBOX mono‐SUMO2/3 conjugation, while a point mutation at K125 had no effect on NOBOX sumoylation. However, NOBOXK97R/K125R double mutants showed loss of mono‐SUMO2/3 and altered higher molecular weight modifications, suggesting cooperation between these lysine's. NOBOXK97R and NOBOXK97R/K125R differentially regulated NOBOX promoter targets, with increased activity on the Gdf9 promoter, but no effect on the Pou5f1 promoter. These data implicate sumoylation as a novel regulatory mechanism for SOHLH1 and NOBOX, which may prove useful in refining their roles during oogenesis as well as their function during reprogramming to generate de novo germ cells.