Biomarkers of Ovarian Reserve

The primary function of the female ovary is the production of a mature and viable oocyte capable of fertilization and subsequent embryo development and implantation. At birth, the ovary contains a finite number of oocytes available for folliculogenesis. This finite number of available oocytes is termed “the ovarian reserve”. The determination of ovarian reserve is important in the assessment and treatment of infertility. As the ovary ages, the ovarian reserve will decline. Infertility affects approximately 15%–20% of reproductive aged couples. The most commonly used biomarker assay to assess ovarian reserve is the measurement of follicle stimulating hormone (FSH) on day 3 of the menstrual cycle. However, anti-müllerian hormone and inhibin-B are other biomarkers of ovarian reserve that are gaining in popularity since they provide direct determination of ovarian status, whereas day 3 FSH is an indirect measurement. This review examines the physical tools and the hormone biomarkers used to evaluate ovarian reserve

New insights into the DT40 B cell receptor cluster using a proteomic proximity labeling assay.

In the vertebrate immune system, each B-lymphocyte expresses a surface IgM-class B cell receptor (BCR). When cross-linked by antigen or anti-IgM antibody, the BCR accumulates with other proteins into distinct surface clusters that activate cell signaling, division, or apoptosis. However, the molecular composition of these clusters is not well defined. Here we describe a quantitative assay we call selective proteomic proximity labeling using tyramide (SPPLAT). It allows proteins in the immediate vicinity of a target to be selectively biotinylated, and hence isolated for mass spectrometry analysis. Using the chicken B cell line DT40 as a model, we use SPPLAT to provide the first proteomic analysis of any BCR cluster using proximity labeling. We detect known components of the BCR cluster, including integrins, together with proteins not previously thought to be BCR-associated. In particular, we identify the chicken B-lymphocyte allotypic marker chB6. We show that chB6 moves to within about 30-40 nm of the BCR following BCR cross-linking, and we show that cross-linking chB6 activates cell binding to integrin substrates laminin and gelatin. Our work provides new insights into the nature and composition of the BCR cluster, and confirms SPPLAT as a useful research tool in molecular and cellular proteomics.JSR supported by Grants BB/J021091 and H024085/1 from the Biotechnology and Biological Sciences Research Council (UK). SWH & RWF supported by Grant G0500707 from the Medical Research Council (UK) and Grant 094470/Z/10/Z from the Wellcome Trust. BS & PEF supported by the DePaul University Research Council. This work was supported in part by grants from the Chinese Ministry of Science and Technology 973 Program (2012CB911000 and 2013CB910700) and the National Natural Science Foundation of China (31110103914, 31070656, 31000342, and 31270794).This is the final version of the article. It was first available from ASBMB via http://dx.doi.org/10.1074/jbc.M113.52957

Population Genomics of Intron Splicing in 38 Saccharomyces cerevisiae Genome Sequences

Introns are a ubiquitous feature of eukaryotic genomes, and the dynamics of intron evolution between species has been extensively studied. However, comparatively few analyses have focused on the evolutionary forces shaping patterns of intron variation within species. To better understand the population genetic characteristics of introns, we performed an extensive population genetics analysis on key intron splice sequences obtained from 38 strains of Saccharomyces cerevisiae. As expected, we found that purifying selection is the dominant force governing intron splice sequence evolution in yeast, formally confirming that intron-containing alleles are a mutational liability. In addition, through extensive coalescent simulations, we obtain quantitative estimates of the strength of purifying selection (2Nes ≈ 19) and use diffusion approximations to provide insights into the evolutionary dynamics and sojourn times of newly arising splice sequence mutations in natural yeast populations. In contrast to previous functional studies, evolutionary analyses comparing the prevalence of introns in essential and nonessential genes suggest that introns in nonribosomal protein genes are functionally important and tend to be actively maintained in natural populations of S. cerevisiae. Finally, we demonstrate that heritable variation in splicing efficiency is common in intron-containing genes with splice sequence polymorphisms. More generally, our study highlights the advantages of population genomics analyses for exploring the forces that have generated extant patterns of genome variation and for illuminating basic biological processes