Protamine 2 deficiency results in Septin 12 abnormalities.

There is a well-established link between abnormal sperm chromatin states and poor motility, however, how these two processes are interdependent is unknown. Here, we identified a possible mechanistic insight by showing that Protamine 2, a nuclear DNA packaging protein in sperm, directly interacts with cytoskeletal protein Septin 12, which is associated with sperm motility. Septin 12 has several isoforms, and we show, that in the sperm, the short one (Mw 36 kDa) is mis-localized, while two long isoforms (Mw 40 and 41 kDa) are unexpectedly lost in sperm chromatin-bound protein fractions.

Cellular heterogeneity and dynamics of the human uterus in healthy premenopausal women.

The human uterus is a complex and dynamic organ whose lining grows, remodels, and regenerates every menstrual cycle or upon tissue damage. Here, we applied single-cell RNA sequencing to profile more the 50,000 uterine cells from both the endometrium and myometrium of five healthy premenopausal individuals, and jointly analyzed the data with a previously published dataset from 15 subjects. The resulting normal uterus cell atlas contains more than 167K cells, representing the lymphatic endothelium, blood endothelium, stromal, ciliated epithelium, unciliated epithelium, and immune cell populations.

Protamine 2 Deficiency Results In Septin 12 Abnormalities.

There is a well-established link between abnormal sperm chromatin states and poor motility, however, how these two processes are interdependent is unknown. Here, we identified a possible mechanistic insight by showing that Protamine 2, a nuclear DNA packaging protein in sperm, directly interacts with cytoskeletal protein Septin 12, which is associated with sperm motility. Septin 12 has several isoforms, and we show, that in the sperm, the short one (Mw 36 kDa) is mislocalized, while two long isoforms (Mw 40 and 41 kDa) are unexpectedly lost in sperm chromatin-bound protein fractions.

Cellular heterogeneity and dynamics of the human uterus in healthy premenopausal women.

Unlabelled: The human uterus is a complex and dynamic organ whose lining grows, remodels, and regenerates in every menstrual cycle or upon tissue damage. Here we applied single-cell RNA sequencing to profile more the 50,000 uterine cells from both the endometrium and myometrium of 5 healthy premenopausal individuals, and jointly analyzed the data with a previously published dataset from 15 subjects. The resulting normal uterus cell atlas contains more than 167K cells representing the lymphatic endothelium, blood endothelium, stromal, ciliated epithelium, unciliated epithelium, and immune cell populations.

Proteomic analysis of human sperm reveals changes in protamine 1 phosphorylation in men with infertility.

Objective: To perform a comprehensive assessment of protamine (P) isoforms and modifications in human sperm with the aim of identifying how P modifications and isoforms are altered in men with reduced sperm motility and low sperm count.

Design: Cross-sectional.

Setting: Academic medical center.

Sperm chromatin structure and reproductive fitness are altered by substitution of a single amino acid in mouse protamine 1.

Conventional dogma presumes that protamine-mediated DNA compaction in sperm is achieved by electrostatic interactions between DNA and the arginine-rich core of protamines. Phylogenetic analysis reveals several non-arginine residues conserved within, but not across species. The significance of these residues and their post-translational modifications are poorly understood.

Placental cell type deconvolution reveals that cell proportions drive preeclampsia gene expression differences.

The placenta mediates adverse pregnancy outcomes, including preeclampsia, which is characterized by gestational hypertension and proteinuria. Placental cell type heterogeneity in preeclampsia is not well-understood and limits mechanistic interpretation of bulk gene expression measures. We generated single-cell RNA-sequencing samples for integration with existing data to create the largest deconvolution reference of 19 fetal and 8 maternal cell types from placental villous tissue (n = 9 biological replicates) at term (n = 40,494 cells).

Myh6 promoter-driven Cre recombinase excises floxed DNA fragments in a subset of male germline cells.

Myh6-Cre transgenic mouse line was known to express Cre recombinase only in the heart. Nevertheless, during breeding Myh6-Cre to Rosa26 reporter (tdTom) mouse line, we observed that a significant part of their F2 tdTom/+ offspring had tdTom reporter gene universally activated. Our results show that Myh6-Cre transgenic mice have Cre recombinase activity in a subpopulation of the male germline cells, and that Myh6 gene transcripts are enriched in the interstitial Leydig cells and the undifferentiated spermatogonia stem cells.

Decoding the Spermatogenesis Program: New Insights from Transcriptomic Analyses.

Spermatogenesis is a complex differentiation process coordinated spatiotemporally across and along seminiferous tubules. Cellular heterogeneity has made it challenging to obtain stage-specific molecular profiles of germ and somatic cells using bulk transcriptomic analyses. This has limited our ability to understand regulation of spermatogenesis and to integrate knowledge from model organisms to humans.

The Art of Packaging the Sperm Genome: Molecular and Structural Basis of the Histone-To-Protamine Exchange.

Male fertility throughout life hinges on the successful production of motile sperm, a developmental process that involves three coordinated transitions: mitosis, meiosis, and spermiogenesis. Germ cells undergo both mitosis and meiosis to generate haploid round spermatids, in which histones bound to the male genome are replaced with small nuclear proteins known as protamines. During this transformation, the chromatin undergoes extensive remodeling to become highly compacted in the sperm head.

Differential impact of a dyskeratosis congenita mutation in TPP1 on mouse hematopoiesis and germline.

Telomerase extends chromosome ends in somatic and germline stem cells to ensure continued proliferation. Mutations in genes critical for telomerase function result in telomeropathies such as dyskeratosis congenita, frequently resulting in spontaneous bone marrow failure. A dyskeratosis congenita mutation in TPP1 (K170∆) that specifically compromises telomerase recruitment to telomeres is a valuable tool to evaluate telomerase-dependent telomere length maintenance in mice.

TCF21 mesenchymal cells contribute to testis somatic cell development, homeostasis, and regeneration in mice.

Testicular development and function rely on interactions between somatic cells and the germline, but similar to other organs, regenerative capacity declines in aging and disease. Whether the adult testis maintains a reserve progenitor population remains uncertain. Here, we characterize a recently identified mouse testis interstitial population expressing the transcription factor Tcf21.

Regulation of meiotic progression by Sertoli-cell androgen signaling.

Androgen receptor (AR) signaling in Sertoli cells is known to be important for germ-cell progression through meiosis, but the extent to which androgens indirectly regulate specific meiotic stages is not known. Here, we combine synchronization of spermatogenesis, cytological analyses and single-cell RNAseq (scRNAseq) in the ertoli-ell ndrogen eceptor nockut (SCARKO) mutant and control mice, and demonstrate that SCARKO mutant spermatocytes exhibited normal expression and localization of key protein markers of meiotic prophase events, indicating that initiation of meiotic prophase is not androgen dependent. However, spermatocytes from SCARKO testes failed to acquire competence for the meiotic division phase.

Single-Cell RNA Sequencing of Human, Macaque, and Mouse Testes Uncovers Conserved and Divergent Features of Mammalian Spermatogenesis.

Spermatogenesis is a highly regulated process that produces sperm to transmit genetic information to the next generation. Although extensively studied in mice, our current understanding of primate spermatogenesis is limited to populations defined by state-specific markers from rodent data. As between-species differences have been reported in the duration and differentiation hierarchy of this process, it remains unclear how molecular markers and cell states are conserved or have diverged from mice to man.

Two Separation-of-Function Isoforms of Human TPP1 Dictate Telomerase Regulation in Somatic and Germ Cells.

Telomerase replicates chromosome ends in germ and somatic stem cells to facilitate their continued proliferation. Telomerase action depends on the telomeric protein TPP1, which recruits telomerase to telomeres and facilitates processive DNA synthesis. Here, we identify separation-of-function long (TPP1-L) and short (TPP1-S) isoforms of TPP1 that appear to be generated from separate transcripts and differ only in 86 amino acids at their N terminus.

Gametogenesis: A journey from inception to conception.

Gametogenesis, the process of forming mature germ cells, is an integral part of both an individual's and a species' health and well-being. This chapter focuses on critical male and female genetic and epigenetic processes underlying normal gamete formation through their differentiation to fertilization. Finally, we explore how knowledge gained from this field has contributed to progress in areas with great clinical promise, such as in vitro gametogenesis.

The Neonatal and Adult Human Testis Defined at the Single-Cell Level.

Spermatogenesis has been intensely studied in rodents but remains poorly understood in humans. Here, we used single-cell RNA sequencing to analyze human testes. Clustering analysis of neonatal testes reveals several cell subsets, including cell populations with characteristics of primordial germ cells (PGCs) and spermatogonial stem cells (SSCs).

A Comprehensive Roadmap of Murine Spermatogenesis Defined by Single-Cell RNA-Seq.

Spermatogenesis requires intricate interactions between the germline and somatic cells. Within a given cross section of a seminiferous tubule, multiple germ and somatic cell types co-occur. This cellular heterogeneity has made it difficult to profile distinct cell types at different stages of development.

Obesity-Induced Infertility in Male Mice Is Associated With Disruption of Crisp4 Expression and Sperm Fertilization Capacity.

Approximately 15% of human couples of reproductive age have impaired fertility, and the male component accounts for about half of these cases. The etiology is usually unknown, but high correlation with the increase in obesity rates is documented. In this study, we show that diet-induced and genetically obese mice display copulatory behavior comparable to controls, but the number of females impregnated by obese males is remarkably low.

Transcription and imprinting dynamics in developing postnatal male germline stem cells.

Postnatal spermatogonial stem cells (SSCs) progress through proliferative and developmental stages to populate the testicular niche prior to productive spermatogenesis. To better understand, we conducted extensive genomic profiling at multiple postnatal stages on subpopulations enriched for particular markers (THY1, KIT, OCT4, ID4, or GFRa1). Overall, our profiles suggest three broad populations of spermatogonia in juveniles: (1) epithelial-like spermatogonia (THY1(+); high OCT4, ID4, and GFRa1), (2) more abundant mesenchymal-like spermatogonia (THY1(+); moderate OCT4 and ID4; high mesenchymal markers), and (3) (in older juveniles) abundant spermatogonia committing to gametogenesis (high KIT(+)).

Chromatin and transcription transitions of mammalian adult germline stem cells and spermatogenesis.

Adult germline stem cells (AGSCs) self-renew (Thy1(+) enriched) or commit to gametogenesis (Kit(+) enriched). To better understand how chromatin regulates AGSC biology and gametogenesis, we derived stage-specific high-resolution profiles of DNA methylation, 5hmC, histone modifications/variants, and RNA-seq in AGSCs and during spermatogenesis. First, we define striking signaling and transcriptional differences between AGSC types, involving key self-renewal and proliferation pathways.

Probabilistic alignment leads to improved accuracy and read coverage for bisulfite sequencing data.

Background: DNA methylation has been linked to many important biological phenomena. Researchers have recently begun to sequence bisulfite treated DNA to determine its pattern of methylation. However, sequencing reads from bisulfite-converted DNA can vary significantly from the reference genome because of incomplete bisulfite conversion, genome variation, sequencing errors, and poor quality bases.

Epigenetic regulation of colon cancer and intestinal stem cells.

The importance and role of the cellular epigenome in cell fating and development have been studied for decades. The epigenome encompasses a range of attributes including DNA methylation, histone modifications, and chromatin remodelers; together these components define the cellular transcriptome, identity, and function. The cellular epigenome is dynamic in response to environmental signals, modifiable during normal cell differentiation and is heritable in daughter cells.

Analysis of gene-specific and genome-wide sperm DNA methylation.

Epigenetic modifications on the DNA sequence (DNA methylation) or on chromatin-associated proteins (i.e., histones) comprise the "cellular epigenome"; together these modifications play an important role in the regulation of gene expression.