Role In Early Embryo Development Research Articles

The mammalian sperm factor phospholipase C zeta is critical for early embryo division and pregnancy in humans and mice.

The mammalian sperm factor phospholipase C zeta is critical for early embryo division and pregnancy in humans and mice.

A long non-coding RNA essential for early embryonic development improves SCNT efficiency in goats.

Although abundant long non-coding RNAs (lncRNAs) have been found to be highly expressed in early embryos, the functions and mechanisms of most lncRNAs in regulating embryonic development remain unclear. This study was conducted to identify the key lncRNAs during embryonic genome activation (EGA) for promoting embryonic development after somatic cell nuclear transfer (SCNT) in goats. We screened and characterized lncRNAs from transcriptome data of in vitro-fertilized, 2-cell (IVF-2c) and 8-cell embryos (IVF-8c) and 8-cell SCNT embryos (SCNT-8c). We obtained 12 differentially expressed lncRNAs that were highly expressed in IVF-8c embryos compared to IVF-2c, and less expressed in SCNT-8c embryos. After target gene prediction, expression verification, and functional deletion experiments, we found that the expression level of lncRNA3720 affected the early embryonic development in goats. We cloned full length lncRNA3720 and over-expressed it in goat fetal fibroblasts (GFFs). We identified histone variants by analyzing the transcriptome data from both GFFs and embryos. Gene annotation of the gene library and literature search revealed that histone variants may have important roles in early embryo development, so we selected them as the potential target genes for lncRNA3720. Lastly, we compensated for the low expression of lncRNA3720 in SCNT embryos by microinjection, and showed that the development rate and quality of SCNT embryos was significantly improved. We speculate that lncRNA3720 is a key promoter of embryonic development in goats by interacting with histone variants.

Progress of Psf1 and prospects in the tumor: A review

Partner of Sld5-1(Psf1) is a member of Gins complex, which was discovered in 2003. It consists of the predominantly α-helical A-domain and the massively β-stranded B-domain. Some researches indicate that Psf1 plays a prominent part in DNA replication through cell cycle regulation, and plays a key role in early embryo development and tissue regeneration. The overexpression of Psf1 in active proliferating cells is closely correlated with the occurrence of tumors. On the side, tumor cells with high Psf1 expression showed high heterogeneity and poor clinical prognosis. In this review, we will review the research progress of Psf1 in cell cycle regulation, immature cell proliferation and oncology.

Nucleoporin37 may play a role in early embryo development in human and mice.

Maternal-effect genes (MEGs) play an important role in maintaining the survival and development of mammalian embryos at the cleavage stage after fertilization. Despite long-term efforts, the MEGs that regulate preimplantation embryo development remain largely unknown. Here, using whole-exome sequencing and homozygosity mapping, we identified a potential candidate gene associated with early embryo development: nucleoporin37 (NUP37), a nucleoporin gene that encodes a member of the nuclear pore complexes and regulates nuclear pore permeability and nucleocytoplasmic transport. Moreover, we determined the temporal and spatial expression patterns of Nup37 in mouse oocytes and early embryos, and explored the role of NUP37 in oocyte maturation and preimplantation embryo development. Immunoprecipitation assays confirmed that yes-associated protein-1 (YAP1) binds to TEA domain transcription factor 4 (TEAD4) and NUP37. Furthermore, Nup37 gene knockdown reduced the nuclear import of YAP1 and down-regulated the expression of YAP1-TEAD pathway downstream genes Rrm2 and Rpl13 in early embryos. Our study provides evidence that maternal NUP37 contributes to the nuclear import of YAP1 and then activates the YAP1-TEAD pathway, a signalling pathway essential for zygotic genome activation. Nup37 may be a key gene involved in preimplantation embryo development in mammals.

Upregulated expression of NOP2 predicts worse prognosis of gastric adenocarcinoma by promoting tumor growth.

: NOP2 nucleolar protein plays a crucial role in early embryo development and cell proliferation. The role of NOP2 in human gastric adenocarcinoma has not been elucidated. In the present study, we aimed to examine the expression levels of NOP2 and dissected whether NOP2 expression was associated with aggressive clinicopathological outcomes of patients with gastric adenocarcinoma. : Clinicopathological analysis was performed in patients with gastric adenocarcinoma. Expression of NOP2 was tested by immunohistochemistry staining and quantitative RT-PCR. The prognostic role of NOP2 in gastric adenocarcinoma patients was assessed by univariate and multivariate analysis. The effect of NOP2 on cell proliferation was examined through cellular experiments and mice models. : NOP2 expression was elevated in gastric adenocarcinoma tissues compared to normal gastric tissues. High expression of NOP2 was significantly correlated with tumor size, invasion depth, and lymph node metastasis. Moreover, patients with high NOP2 expression had poorer overall survival, and NOP2 was identified as an independent prognosis factor. Using the gastric adenocarcinoma cells, we found that NOP2 can promote tumor cell proliferation both in vitro and in vivo. : Overexpression of NOP2 significantly correlates with a poorer prognosis of gastric adenocarcinoma patients and suggested the potential of NOP2, which may serve as a novel prognostic biomarker in gastric adenocarcinoma.

The seminal plasma proteins Peptidyl arginine deaminase 2, rRNA adenine N (6)-methyltransferase and KIAA0825 are linked to better motility post thaw in stallions

Seminal plasma plays an important role in sperm physiology. Seminal plasma proteins vehiculated in microvesicles, carry RNAs and proteins with a potential role in early embryo development. Additionally, proteins present in seminal plasma participate in redox regulation and energy metabolism. In view of these facts, we hypothesized that differences in protein composition of the seminal plasma among stallions may help to explain differences in freeze-ability seen among them. Three independent ejaculates from 10 different stallions of varying breeds were frozen using standard protocols in our laboratory. Aliquots of the ejaculate were separated and stored at −80 °C until further proteomic analysis. Semen analysis was performed using computer assisted sperm analysis and flow cytometry. Significant differences in proteome composition of seminal plasma were observed in the group of stallions showing better motility post thaw. 3116 proteins were identified, and of these, 34 were differentially expressed in stallions with better motility post thaw, 4 of them were also differentially expressed in stallions with different percentages of linearly motile sperm post thaw and 1 protein, Midasin, was expressed in stallions showing high circular velocity post thaw.Seminal plasma proteins may play a major role in sperm functionality; being vehiculated through extracellular vesicles and participating in sperm physiology. Bioinformatic analysis identifies discriminant proteins able to predict the outcome of cryopreservation, identifying potential new biomarkers to assess ejaculate quality.

P–181 Morphine regulates BMP4 growth factor and is involved in in-vitro early embryo development and PGCs formation

Abstract Study question To elucidate if morphine can alter embryo development. Summary answer Chronic morphine treatment regulates BMP4 growth factor, in terms of gene expression and H3K27me3 enrichment and promotes in-vitro blastocysts development and PGC formation. What is known already BMP4 is a member of the bone morphogenetic protein family, which acts mainly through SMAD dependent pathway, to play an important role in early embryo development. Indeed, BMP4 enhances pluripotency in mouse embryonic stem cells (mESCs) and, specifically, is involved in blastocysts formation and primordial germ cells (PGCs) generation. Although, external morphine influence has been previously reported on the early embryo development, focus on implantation and uterus function, there is a big concern in understanding how environmental factors can cause stable epigenetic changes, which could be maintained during development and lead to health problems. Study design, size, duration First, OCT4-reported mESCs were chronically treated with morphine during 24h, 10–5mM. After morphine removal, mESCs were collected for RNA-seq and H3K27me3 ChIP-seq study. To elucidate the role of morphine in early embryo development, two cell- embryos stage were chronically treated with morphine for 24h and in-vitro cultured up to the blastocyst stage in the absence of morphine. Furthermore, after morphine treatment mESCs were differentiated to PGCs, to elucidate the role of morphine in PGC differentiation. Participants/materials, setting, methods Transcriptomic analyses and H3K27me3 genome wide distribution were carried out by RNA-Sequencing and Chip-Sequencing respectively. Validations were performed by RNA-RT-qPCR and Chip-RT-qPCR. Main results and the role of chance Dynamic transcriptional analyses identified a total of 932 differentially expressed genes (DEGs) after morphine treatment on mESCs, providing strong evidence of a transcriptional epigenetic effect induced by morphine. High-throughput screening approaches showed up Bmp4 as one of the main morphine targets on mESCs. Morphine caused an up-regulation of Bmp4 gene expression together with a decrease of H3K27me3 enrichment at promoter level. However, no significant differences were observed on gene expression and H3K27me3 enrichment on BMP4 signaling pathway components (such as Smad1, Smad4, Smad5, Smad7, Prdm1 and Prmd14) after morphine treatment. On the other hand, the Bmp4 gene expression was also up-regulated in in-vitro morphine treated blastocyst and in-vitro morphine treated PGCs. These results were consistent with the increase in blastocyst rate and PGC transformation rate observed after morphine chronic treatment. Limitations, reasons for caution To perform the in-vitro analysis. Further studies are needed to describe the whole signaling pathways underlying BMP4 epigenetic regulation after morphine treatment. Wider implications of the findings: Our findings confirmed that mESCs and two-cell embryos are able to memorize morphine exposure and promote both blastocyst development and PGCs formation through potentially BMP4 epigenetic regulation. These results provide insights understanding how environmental factors can cause epigenetic changes during the embryo development, leading to alterations and producing health problems/diseases Trial registration number Not applicable

P-181 Morphine regulates BMP4 growth factor and is involved in in-vitro early embryo development and PGCs formation

Abstract Study question To elucidate if morphine can alter embryo development. Summary answer Chronic morphine treatment regulates BMP4 growth factor, in terms of gene expression and H3K27me3 enrichment and promotes in-vitro blastocysts development and PGC formation. What is known already BMP4 is a member of the bone morphogenetic protein family, which acts mainly through SMAD dependent pathway, to play an important role in early embryo development. Indeed, BMP4 enhances pluripotency in mouse embryonic stem cells (mESCs) and, specifically, is involved in blastocysts formation and primordial germ cells (PGCs) generation. Although, external morphine influence has been previously reported on the early embryo development, focus on implantation and uterus function, there is a big concern in understanding how environmental factors can cause stable epigenetic changes, which could be maintained during development and lead to health problems. Study design, size, duration First, OCT4-reported mESCs were chronically treated with morphine during 24h, 10-5mM. After morphine removal, mESCs were collected for RNA-seq and H3K27me3 ChIP-seq study. To elucidate the role of morphine in early embryo development, two cell- embryos stage were chronically treated with morphine for 24h and in-vitro cultured up to the blastocyst stage in the absence of morphine. Furthermore, after morphine treatment mESCs were differentiated to PGCs, to elucidate the role of morphine in PGC differentiation. Participants/materials, setting, methods Transcriptomic analyses and H3K27me3 genome wide distribution were carried out by RNA-Sequencing and Chip-Sequencing respectively. Validations were performed by RNA-RT-qPCR and Chip-RT-qPCR. Main results and the role of chance Dynamic transcriptional analyses identified a total of 932 differentially expressed genes (DEGs) after morphine treatment on mESCs, providing strong evidence of a transcriptional epigenetic effect induced by morphine. High-throughput screening approaches showed up Bmp4 as one of the main morphine targets on mESCs. Morphine caused an up-regulation of Bmp4 gene expression together with a decrease of H3K27me3 enrichment at promoter level. However, no significant differences were observed on gene expression and H3K27me3 enrichment on BMP4 signaling pathway components (such as Smad1, Smad4, Smad5, Smad7, Prdm1 and Prmd14) after morphine treatment. On the other hand, the Bmp4 gene expression was also up-regulated in in-vitro morphine treated blastocyst and in-vitro morphine treated PGCs. These results were consistent with the increase in blastocyst rate and PGC transformation rate observed after morphine chronic treatment. Limitations, reasons for caution To perform the in-vitro analysis. Further studies are needed to describe the whole signaling pathways underlying BMP4 epigenetic regulation after morphine treatment. Wider implications of the findings Our findings confirmed that mESCs and two-cell embryos are able to memorize morphine exposure and promote both blastocyst development and PGCs formation through potentially BMP4 epigenetic regulation. These results provide insights understanding how environmental factors can cause epigenetic changes during the embryo development, leading to alterations and producing health problems/diseases. Trial registration number not applicable

LIN28 coordinately promotes nucleolar/ribosomal functions and represses the 2C-like transcriptional program in pluripotent stem cells

LIN28 is an RNA binding protein with important roles in early embryo development, stem cell differentiation/reprogramming, tumorigenesis and metabolism. Previous studies have focused mainly on its role in the cytosol where it interacts with Let-7 microRNA precursors or mRNAs, and few have addressed LIN28’s role within the nucleus. Here, we show that LIN28 displays dynamic temporal and spatial expression during murine embryo development. Maternal LIN28 expression drops upon exit from the 2-cell stage, and zygotic LIN28 protein is induced at the forming nucleolus during 4-cell to blastocyst stage development, to become dominantly expressed in the cytosol after implantation. In cultured pluripotent stem cells (PSCs), loss of LIN28 led to nucleolar stress and activation of a 2-cell/4-cell-like transcriptional program characterized by the expression of endogenous retrovirus genes. Mechanistically, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to nucleolar phase separation defects, ribosomal stress and activation of P53 which in turn binds to and activates 2C transcription factor Dux. LIN28 also resides in a complex containing the nucleolar factor Nucleolin (NCL) and the transcriptional repressor TRIM28, and LIN28 loss leads to reduced occupancy of the NCL/TRIM28 complex on the Dux and rDNA loci, and thus de-repressed Dux and reduced rRNA expression. Lin28 knockout cells with nucleolar stress are more likely to assume a slowly cycling, translationally inert and anabolically inactive state, which is a part of previously unappreciated 2C-like transcriptional program. These findings elucidate novel roles for nucleolar LIN28 in PSCs, and a new mechanism linking 2C program and nucleolar functions in PSCs and early embryo development.

Impact of trace mineral source on beef replacement heifer growth, reproductive development, and biomarkers of maternal recognition of pregnancy and embryo survival.

Trace minerals are known to play important roles in early embryo development. The study objective was to determine effects of trace mineral source on heifer reproductive performance. Beef heifers (n = 129) were randomly assigned to one of two treatments. From weaning through breeding, all heifers were individually fed a basal diet supplemented with cobalt (Co), copper (Cu), manganese (Mn), and zinc (Zn) either from organic sources (COMP; Cu, Mn, and Zn amino acid complexes and Co glucoheptonate; Availa-4, Zinpro Corporation, Eden Prairie, MN) or inorganic sources (INORG; Cu, Mn, and Zn hydroxychlorides; Intellibond C, M, and Z, Micronutrients, Indianapolis, IN) and Co as CoSO4. Blood samples and a reproductive tract score (RTS) were collected to determine pubertal status. All animals were synchronized and artificially inseminated. Pregnancy status was determined by lymphocyte gene expression, circulating concentrations of pregnancy-associated glycoproteins (PAGs), and by transrectal ultrasonography after artificial insemination. Embryonic loss was defined as when a previously pregnant animal was subsequently diagnosed not pregnant. Data were analyzed using the MIXED procedure in SAS. Puberty (P = 0.44), pelvic area (P = 0.74), RTS (P = 0.49), and estrus expression (P = 0.82) were not influenced by treatment. There was no effect of treatment (P = 0.37) or treatment by time (P = 0.19) on pregnancy, but there was a tendency (P = 0.13) for decreased embryonic loss among COMP heifers (27 ± 6%) compared to INORG heifers (38 ± 6%). There was a treatment by pregnancy status by time interaction (P < 0.01) on circulating PAG concentrations with PAG concentrations tending (P = 0.08) to be greater on day 25 among heifers in the COMP treatment compared to heifers in the INORG group. In summary, source of trace mineral did not affect puberty, RTS, pelvic area, or overall pregnancy success, but feeding complexed trace minerals tended to increase circulating PAG concentrations and embryo survival.

Pluripotency and Growth Factors in Early Embryonic Development of Mammals: A Comparative Approach.

The regulation of early events in mammalian embryonic development is a complex process. In the early stages, pluripotency, cellular differentiation, and growth should occur at specific times and these events are regulated by different genes that are expressed at specific times and locations. The genes related to pluripotency and cellular differentiation, and growth factors that determine successful embryonic development are different (or differentially expressed) among mammalian species. Some genes are fundamental for controlling pluripotency in some species but less fundamental in others, for example, Oct4 is particularly relevant in bovine early embryonic development, whereas Oct4 inhibition does not affect ovine early embryonic development. In addition, some mechanisms that regulate cellular differentiation do not seem to be clear or evolutionarily conserved. After cellular differentiation, growth factors are relevant in early development, and their effects also differ among species, for example, insulin-like growth factor improves the blastocyst development rate in some species but does not have the same effect in mice. Some growth factors influence genes related to pluripotency, and therefore, their role in early embryo development is not limited to cell growth but could also involve the earliest stages of development. In this review, we summarize the differences among mammalian species regarding the regulation of pluripotency, cellular differentiation, and growth factors in the early stages of embryonic development.

Protein regulator of cytokinesis 1 regulates chromosome dynamics and cytoplasmic division during mouse oocyte meiotic maturation and early embryonic development.

In contrast to the homeokinesis of mitosis, asymmetric division of cytoplasm is the conspicuous feature of meiosis in mammalian oocytes. Protein regulator of cytokinesis 1 (PRC1) is an important regulator during mitotic spindle assembly and cytoplasmic division, but its functions in oocyte meiosis and early embryo development have not been fully elucidated. In this study, we detected PRC1 expression and localization and revealed a nuclear, spindle midzone-related dynamic pattern throughout meiotic and mitotic progressions. Treatment of oocytes with the reagents taxol or nocodazole disturbed the distribution of PRC1 in metaphase II oocytes. Further, PRC1 depletion led to failure of first polar body (PB1) extrusion and spindle migration, aneuploidy and defective kinetochore-microtubule attachment and spindle assembly. Overexpression of PRC1 resulted in PB1 extrusion failure, aneuploidy and serious defects of spindle assembly. To investigate PRC1 function in early embryos, we injected Prc1 morpholino into zygotes and 2-cell stage embryos. Depletion of PRC1 in zygotes impaired 4-cell, morula and blastocyst formation. Loss of PRC1 in single or double blastomeres in 2-cell stage embryos significantly impaired cell division, indicating its indispensable role in early embryo development. Co-immunoprecipitation showed that PRC1 interacts with polo-like kinase 1 (PLK1), and functional knockdown and rescue experiments demonstrated that PRC1 recruits PLK1 to the spindle midzone to regulate cytoplasmic division during meiosis. Finally, kinesin family member 4 knockdown downregulates PRC1 expression and leads to PRC1 localization failure. Taken together, our data suggest PRC1 plays an important role during oocyte maturation and early embryonic development by regulating chromosome dynamics and cytoplasmic division.

Human sperm tsRNA as potential biomarker and therapy target for male fertility.

Infertility caused by male factors is routinely diagnosed by assessing traditional semen parameters. Growing evidence has indicated that the tsRNAs carried in sperm act as epigenetic factors and potential biomarkers for the assessment of sperm quality. We recently demonstrated that tRNAGln-TTG derived small RNAs played notable roles in the first cleavage of a porcine embryo. However, the function of human sperm tRNAGln-TTG derived small RNAs as a diagnostic biomarker and its role in early embryo development remains unclear. In this study, we found that human sperm tRNAGln-TTG derived small RNAs were highly associated with sperm quality. By microinjecting the antisense sequence into human tripronuclear (3PN) zygotes followed by single-cell RNA-sequencing, we found that human sperm tRNAGln-TTG derived small RNAs participated in the development of a human embryo. Furthermore, Gln-TTGs might influence embryonic genome activation by modulating noncoding RNA processing. These findings demonstrated that human sperm tRNAGln-TTG derived small RNAs could be potential diagnostic biomarkers and could be used as a clinical target for male infertility.

383 Effect of trace mineral source on heifer reproductive performance

Abstract Trace minerals are known to play important roles in early embryo development. The study objective was to determine effects of trace mineral source on heifer reproductive performance. Over two years, beef heifers (n = 130) were randomly assigned to two pens and two treatments, within each pen, based on breed, age, and BW. From weaning through the breeding season, all heifers were individually fed a basal diet of grass hay, corn silage, and a supplement pellet (soybean hulls, dried distiller’s grains plus solubles, minerals, vitamins and monensin). Cobalt, Cu, Mn, and Zn were supplemented with either complexed sources (Availa-4) or inorganic sources (Cu, Mn, and Zn hydroxychlorides; Intellibond C, M, and Z) and Co as CoSO4. Blood samples were collected bi-weekly, and a reproductive tract score (RTS) was collected 30 d prior to breeding to determine pubertal status. All animals were synchronized and artificially inseminated (AI). Pregnancy status was determined by lymphocyte gene expression on d 17, 19, and 21; by circulating concentrations of pregnancy associated glycoproteins (PAGs) on d 22, 23, 24, 25, 26, 27, and 28; and by transrectal ultrasonography on d 30 and 60 after AI. Embryonic loss was defined as when a previously pregnant animal was subsequently diagnosed not pregnant. Data were analyzed using the MIXED procedure in SAS. Puberty (P = 0.44), pelvic area (P = 0.74), RTS (P = 0.49), and estrus expression (P = 0.82) were not influenced by treatment. There was no effect of treatment (P = 0.37) or treatment by time (P = 0.19) on pregnancy, but there was a weak tendency (P = 0.13) for decreased embryonic loss among heifers supplemented with complexed trace minerals (27±6%) compared to inorganic minerals (38±6%). In summary, source of trace mineral did not affect puberty, RTS, pelvic area, or overall pregnancy success, but feeding complexed trace minerals tended to increase embryo survival from d 17 to 60.

Exploratory analysis of transposable elements expression in the C. elegans early embryo

BackgroundTransposable Elements (TE) are mobile sequences that make up large portions of eukaryote genomes. The functions they play within the complex cellular architecture are still not clearly understood, but it is becoming evident that TE have a role in several physiological and pathological processes. In particular, it has been shown that TE transcription is necessary for the correct development of mice embryos and that their expression is able to finely modulate transcription of coding and non-coding genes. Moreover, their activity in the central nervous system (CNS) and other tissues has been correlated with the creation of somatic mosaicisms and with pathologies such as neurodevelopmental and neurodegenerative diseases as well as cancers.ResultsWe analyzed TE expression among different cell types of the Caenorhabditis elegans (C. elegans) early embryo asking if, where and when TE are expressed and whether their expression is correlated with genes playing a role in early embryo development. To answer these questions, we took advantage of a public C. elegans embryonic single-cell RNA-seq (sc-RNAseq) dataset and developed a bioinformatics pipeline able to quantify reads mapping specifically against TE, avoiding counting reads mapping on TE fragments embedded in coding/non-coding transcripts. Our results suggest that i) canonical TE expression analysis tools, which do not discard reads mapping on TE fragments embedded in annotated transcripts, may over-estimate TE expression levels, ii) Long Terminal Repeats (LTR) elements are mostly expressed in undifferentiated cells and might play a role in pluripotency maintenance and activation of the innate immune response, iii) non-LTR are expressed in differentiated cells, in particular in neurons and nervous system-associated tissues, and iv) DNA TE are homogenously expressed throughout the C. elegans early embryo development.ConclusionsTE expression appears finely modulated in the C. elegans early embryo and different TE classes are expressed in different cell types and stages, suggesting that TE might play diverse functions during early embryo development.

AtBUD13 affects pre-mRNA splicing and is essential for embryo development in Arabidopsis.

Pre-mRNA splicing is an important step for gene expression regulation. Yeast Bud13p (bud-site selection protein 13) regulates the budding pattern and pre-mRNA splicing in yeast cells; however, no Bud13p homologs have been identified in plants. Here, we isolated two mutants that carry T-DNA insertions at the At1g31870 locus and shows early embryo lethality and seed abortion. At1g31870 encodes an Arabidopsis homolog of yeast Bud13p, AtBUD13. Although AtBUD13 homologs are widely distributed in eukaryotic organisms, phylogenetic analysis revealed that their protein domain organization is more complex in multicellular species. AtBUD13 is expressed throughout plant development including embryogenesis and AtBUD13 proteins is localized in the nucleus in Arabidopsis. RNA-seq analysis revealed that AtBUD13 mutation predominantly results in the intron retention, especially for shorter introns (≤100 bases). Within this group of genes, we identified 52 genes involved in embryogenesis, out of which 22 are involved in nucleic acid metabolism. Our results demonstrate that AtBUD13 plays critical roles in early embryo development by effecting pre-mRNA splicing.

The contribution of human sperm proteins to the development and epigenome of the preimplantation embryo.

Knowledge of the proteomic composition of the gametes is essential to understand reproductive functions. Most of the sperm proteins are related to spermatogenesis and sperm function, but less abundant protein groups with potential post-fertilization roles have also been detected. The current data are challenging our understanding of sperm biology and functionality, demanding an integrated analysis of the proteomic and RNA-seq datasets available for spermatozoa, oocytes and early embryos, in order to unravel the impact of the male gamete on the generation of the new individual. The aim of this review is to compile human sperm proteins and to identify and infer their origin and discuss their relevance during oocyte fecundation, preimplantation embryogenesis and epigenetic inheritance. The scientific literature was comprehensively searched for proteomic studies on human sperm, oocytes, embryos, and additional reproductive cells and fluids. Proteins were compiled and functionally classified according to Gene Ontology annotations and the mouse phenotypes integrated into the Mouse Genome Informatics database. High-throughput RNA datasets were used to decipher the origin of embryo proteins. The tissue origin of sperm proteins was inferred on the basis of RNA-seq and protein data available in the Human Protein Atlas database. So far, 6871 proteins have been identified and reported in sperm, 1376 in the oocyte and 1300 in blastocyst. With a deeper analysis of the sperm proteome, 103 proteins with known roles in the processes of fertilization and 93 with roles in early embryo development have been identified. Additionally, 560 sperm proteins have been found to be involved in modulating gene expression by regulation of transcription, DNA methylation, histone post-translational modifications and non-coding RNA biogenesis. Some of these proteins may be critical for gene expression regulation after embryo genome activation, and therefore, may be potentially involved in epigenetic transmission of altered phenotypes. Furthermore, the integrative analysis of the sperm, oocyte and blastocyst proteomes and transcriptomes revealed a set of embryo proteins with an exclusive paternal origin, some of which are crucial for correct embryogenesis and, possibly, for modulation of the offspring phenotype. The analysis of the expression of sperm proteins, at both RNA and protein levels, in tissues not only from the male reproductive tract but also from peripheral organs, has suggested a putative extra-testicular origin for some sperm proteins. These proteins could be imported into sperm from the accessory sex glands and other tissues, most likely through exosomes. These integrative proteome and transcriptome analyses focused on specific groups of proteins, rather than on enriched pathways, identified important sperm proteins which may be involved in early embryogenesis and provided evidence which could support the hypothesis of paternal epigenetic inheritance. The putative extra-testicular origin of some sperm proteins suggests not only the involvement of accessory sex glands in fertilization and epigenetic information transmission, but also that some proteins from additional organs could possibly contribute information to the offspring phenotype. These findings should stimulate further research in the field.

Embryonic POU5F1 is Required for Expanded Bovine Blastocyst Formation

POU5F1 is a transcription factor and master regulator of cell pluripotency with indispensable roles in early embryo development and cell lineage specification. The role of embryonic POU5F1 in blastocyst formation and cell lineage specification differs between mammalian species but remains completely unknown in cattle. The CRISPR/Cas9 system was utilized for targeted disruption of the POU5F1 gene by direct injection into zygotes. Disruption of the bovine POU5F1 locus prevented blastocyst formation and was associated with embryonic arrest at the morula stage. POU5F1 knockout morulas developed at a similar rate as control embryos and presented a similar number of blastomeres by day 5 of development. Initiation of SOX2 expression by day 5 of development was not affected by lack of POU5F1. On the other hand, CDX2 expression was aberrant in embryos lacking POU5F1. Notably, the phenotype observed in bovine POU5F1 knockout embryos reveals conserved functions associated with loss of human embryonic POU5F1 that differ from Pou5f1- null mice. The similarity observed in transcriptional regulation of early embryo development between cattle and humans combined with highly efficient gene editing techniques make the bovine a valuable model for human embryo biology with expanded applications in agriculture and assisted reproductive technologies.

Sin3a-Tet1 interaction activates gene transcription and is required for embryonic stem cell pluripotency.

Sin3a is a core component of histone-deacetylation-activity-associated transcriptional repressor complex, playing important roles in early embryo development. Here, we reported that down-regulation of Sin3a led to the loss of embryonic stem cell (ESC) self-renewal and skewed differentiation into mesendoderm lineage. We found that Sin3a functioned as a transcriptional coactivator of the critical Nodal antagonist Lefty1 through interacting with Tet1 to de-methylate the Lefty1 promoter. Further studies showed that two amino acid residues (Phe147, Phe182) in the PAH1 domain of Sin3a are essential for Sin3a–Tet1 interaction and its activity in regulating pluripotency. Furthermore, genome-wide analyses of Sin3a, Tet1 and Pol II ChIP-seq and of 5mC MeDIP-seq revealed that Sin3a acted with Tet1 to facilitate the transcription of a set of their co-target genes. These results link Sin3a to epigenetic DNA modifications in transcriptional activation and have implications for understanding mechanisms underlying versatile functions of Sin3a in mouse ESCs.

Embryonic lethality in mice lacking Trim59 due to impaired gastrulation development

TRIM family members have been implicated in a variety of biological processes such as differentiation and development. We here found that Trim59 plays a critical role in early embryo development from blastocyst stage to gastrula. There existed delayed development and empty yolk sacs from embryonic day (E) 8.5 in Trim59−/− embryos. No viable Trim59−/− embryos were observed beyond E9.5. Trim59 deficiency affected primary germ layer formation at the beginning of gastrulation. At E6.5 and E7.5, the expression of primary germ layer formation-associated genes including Brachyury, lefty2, Cer1, Otx2, Wnt3, and BMP4 was reduced in Trim59−/− embryos. Homozygous mutant embryonic epiblasts were contracted and the mesoderm was absent. Trim59 could interact with actin- and myosin-associated proteins. Its deficiency disturbed F-actin polymerization during inner cell mass differentiation. Trim59-mediated polymerization of F-actin was via WASH K63-linked ubiquitination. Thus, Trim59 may be a critical regulator for early embryo development from blastocyst stage to gastrula through modulating F-actin assembly.