A novel variant in the promoter region of miR-9 gene strongly affects litter size in Markhoz goats

miR-423 sponged by lncRNA NORHA inhibits granulosa cell apoptosis

BACKGROUND

Atresia and degeneration, a follicular developmental fate that reduces female fertility and is triggered by granulosa cell (GC) apoptosis, have been induced by dozens of miRNAs. Here, we report a miRNA, miR-423, that inhibits the initiation of follicular atresia (FA), and early apoptosis of GCs.

RESULTS

We showed that miR-423 was down-regulated during sow FA, and its levels in follicles were negatively correlated with the GC density and the P4/E2 ratio in the follicular fluid in vivo. The in vitro gain-of-function experiments revealed that miR-423 suppresses cell apoptosis, especially early apoptosis in GCs. Mechanically speaking, the miR-423 targets and interacts with the 3'-UTR of the porcine SMAD7 gene, which encodes an apoptosis-inducing factor in GCs, and represses its expression and pro-apoptotic function. Interestingly, FA and the GC apoptosis-related lncRNA NORHA was demonstrated as a ceRNA of miR-423. Additionally, we showed that a single base deletion/insertion in the miR-423 promoter is significantly associated with the number of stillbirths (NSB) trait of sows.

CONCLUSION

These results demonstrate that miR-423 is a small molecule for inhibiting FA initiation and GC early apoptosis, suggesting that treating with miR-423 may be a novel approach for inhibiting FA initiation and improving female fertility.

Two single nucleotide variants in the miR-23a promoter affect granulosa cell apoptosis

microRNAs (miRNAs) are well known to be important in mammalian female fertility. However, the genetic regulation of miRNAs associated with female fertility remains largely unknown. Here, we report that two single-nucleotide variants (SNVs) in the miR-23a promoter strongly influence miR-23a transcription and function in granulosa cell (GC) apoptosis. Two novel SNVs, g.-283G>C and g.-271C>T, were detected in the porcine miR-23a promoter by pooled-DNA sequencing. Furthermore, SNVs in the promoter region influenced miR-23a transcription in porcine GCs by altering its promoter activity. Functionally, SNVs in the promoter strongly influenced miR-23a regulation of early apoptosis in porcine GCs cultured in vitro. In addition, a preliminary association analysis showed that the combined genotypes of the two SNVs, rather than a single SNV, were tentatively associated with sow fertility traits in a Large White population. Overall, our findings suggest that the SNVs g.-283G>C and g.-271C>T in the miR-23a promoter are causal variants affecting GC apoptosis and miR-23a may be a potential small-molecule nonhormonal drug for regulating female fertility.

Dynamic regulation of the transcriptome and proteome of the equine embryo during maternal recognition of pregnancy

During initial maternal recognition of pregnancy (MRP), the equine embryo displays a series of unique events characterized by rapid blastocyst expansion, secretion of a diverse array of molecules, and transuterine migration to interact with the uterine surface. Up to date, the intricate transcriptome and proteome changes of the embryo underlying these events have not been critically studied in horses. Thus, the objective of this study was to perform an integrative transcriptomic (including mRNA, miRNAs, and other small non-coding RNAs) and proteomic analysis of embryos collected from days 10 to 13 of gestation. The results revealed dynamic transcriptome profiles with a total of 1311 differentially expressed genes, including 18 microRNAs (miRNAs). Two main profiles for mRNAs and miRNAs were identified, one with higher expression in embryos ≤5 mm and the second with higher expression in embryos ≥7 mm. At the protein level, similar results were obtained, with 259 differentially abundant proteins between small and large embryos. Overall, the findings demonstrated fine-tuned transcriptomic and proteomic regulations in the developing embryo associated with embryo growth. The identification of specific regulation of mRNAs, proteins, and miRNAs on days 12 and 13 of gestation suggested these molecules as pivotal for embryo development and as involved in MRP, and in establishment of pregnancy in general. In addition, the results revealed new insights into prostaglandin synthesis by the equine embryo, miRNAs and genes potentially involved in modulation of the maternal immune response, regulation of endometrial receptivity and of late implantation in the mare.

Genome-wide association study reveals novel candidate genes for litter size in Markhoz goats

Introduction

The Markhoz goat is the only breed that can produce high-quality fiber called mohair in Iran; however, the size of its population has faced a dramatic decline during the last decades, mainly due to the reluctance of farmers to rear Markhoz goats caused by a reduction in goat production income. Litter size at birth (LSB) and weaning (LSW) are two economically important reproductive traits for local goat breeders and have the potential of increasing the population growth rate. The present study was aimed to identify possible genomic regions that are associated with LSB and LSW in Markhoz goats using a genome-wide association study (GWAS).

Methods

To this end, 136 Markhoz goats with record(s) of kidding were selected for GWAS using the Illumina Caprine 50K bead chip. The individual breeding values (BV) of available LSB and LSW records estimated under an animal mixed model were used as the dependent variable in the GWAS, thereby incorporating repeated categorical variables of litter size.

Results

Four SNPs on chromosomes 2, 20 and 21 were identified to be significantly associated (FDR p < 0.05) with LSB after multiple testing correction under a Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model. Least-square analysis was performed to investigate the effects of detected genotypes on LSB. Ultimately, the GWAS results introduced six candidate genes, including GABRA5, AKAP13, SV2B, PPP1R1C, SSFA2 and TRNAS-GCU in a 100 kb adjacent region of the identified SNPs. Previous studies proposed functional roles of GABRA5 and AKAP13 genes in reproductive processes; however, the role of other candidate genes in reproduction is not clear.

Conclusion

These findings warrant further investigation for use in marker-assisted selection programs in Markhoz goats.

Sensitivity and applications of the PCR Single-Strand Conformation Polymorphism method

PCR Single-Strand Conformation Polymorphism is a method used to identify and detect mutations and is now well known for its many applications on living beings. This paper will discuss the experimental details, limitations and sensitivity of the PCR Single-Strand Conformation Polymorphism method in relation to all existing literature available to us until today. Genomic DNA extraction, PCR amplification and Single-Strand Conformation Polymorphism conditions (concentration of polyacrylamide slab gel electrophoresis, dissociation treatment of double- stranded DNA) and comparison with PCR Restriction Fragment Length Polymorphism are presented. Since its discovery in 1989, there have been many variations, innovations, and modifications of the method, which makes it very easy, safe, fast and for this reason widely applied in clinical diagnostic, forensic medicine, biochemical, veterinary, microbiological, food and environmental laboratories. One of the possible applications of the method is the diagnosis and identification of mutations in new strains of coronaviruses, because science needs more tools to tackle the problem of this pandemic. The PCR Single-Strand Conformation Polymorphism method can be applied in many cases provided that control samples are available and the required conditions of the method are achieved.