Transcriptome analysis of sheep follicular development during prerecruitment, dominant, and mature stages after FSH superstimulation

Identification of hub genes associated with follicle development in multiple births sheep by WGCNA

Sheep exhibit a distinct estrous cycle that includes four different phases: proestrus, estrus, late estrus, and luteal phase. As the estrous cycle repeats, follicular development regularly alternates. We thus investigated ovarian transcriptome data from each of the four phases using weighted gene co-expression network analysis (WGCNA) to identify modules, pathways, and genes essential to follicle growth and development. We clustered mRNA and long non-coding RNA (lncRNA) into different modules by WGCNA, and calculated correlation coefficients between genes and Stages of the estrous cycle. Co-expression of the black module (cor = 0.81, P<0.001) and the yellow module (cor = 0.61, P<0.04) was found to be critical for follicle growth and development. A total of 2066 genes comprising the black and yellow modules was used for functional enrichment. The results reveal that these genes are mainly enriched in Cell cycle, PI3K-Akt signaling pathway, Oocyte meiosis, Apoptosis, and other important signaling pathways. We also identified seven hub genes (BUB1B, MAD2L1, ASPM, HSD3B1, WDHD1, CENPA, and MXI1) that may play a role in follicle development. Our study may provide several important new markers allowing in depth exploration of the genetic basis for multiparous reproduction in sheep.

Effects of different energy diets on DNA methylation and mRNA expression in follicle stimulating hormone receptor gene promoter region of Duolang sheep during estrus

BACKGROUND

The aim of this study was to study the relationship between the methylation level of the promoter region of follicle-stimulating hormone receptor (FSHR) gene and the mRNA expression of Duolang sheep fed different energy diets.

METHODS

In this study, polyembryo estrus Duolang sheep under different energy levels were selected as the experimental subjects. Dietary nutrient level reference (NY/T 816-2004), medium energy level was 10.88 MJ/day, high and low energy groups were increased and decreased by 15% on the basis of medium energy level, respectively 12.51 MJ/day, 9.25 MJ/day. Through RNA and DNA extraction, qPCR, bisulfitegenomicse-quencing PCR (BSP), sequence matching and other analysis of ovarian tissue of Duolang sheep. The difference of DNA methylation level and mRNA expression of FSHR gene during estrus in Duolang sheep fed with different energy diets was detected.

RESULTS

The results showed the expression level of FSHR in high energy group was significantly higher than that in low energy group (P < 0.01), the expression level of FSHR in high energy group was significantly higher than that in medium energy group (P < 0.05), and the expression level of FSHR in medium energy group was significantly higher than that in low energy group (P < 0.05). In the target fragment of the promoter region of the FSHR gene, the methylation rate was 25% in the high energy group, 50% in the normal group, and 75% in the low energy group.

CONCLUSIONS

This study revealed that different dietary energy levels had certain effects on the FSHR gene DNA methylation level and mRNA expression, and the expression level was negatively correlated with methylation level.