Targeting GNAQ in hypothalamic nerve cells to regulate seasonal estrus in sheep

Effects of INSL3 and WNT2B gene polymorphisms on seasonal reproductive traits of Xinjiang Qira black sheep, Kazakh sheep and Duolang sheep

The purpose of this study was to investigate the polymorphism and genetic correlation of INSL3 and WNT2B genes with seasonal estrus and litter size in three different Xinjiang sheep breeds. The genetic diversity of INSL3 and WNT2B genes were analyzed, and their association with litter size and estrous traits were analyzed. The results showed that two SNPs (SNP1, SNP2) were detected in INSL3 gene and there were three genotypes in SNP2 (INSL3 (A100T)), named of AA, AT and TT, A was the dominant allele. Additionally, five SNPs (SNP3, SNP4, SNP5, SNP6, SNP7) were detected in the WNT2B gene and there were three genotypes in SNP4 (WNT2B (G126T)), named GG, GT and TT, G was dominant allele. SNP2 was in Hardy-Weinberg equilibrium in three sheep breeds (P > 0.05). SNP4 was deviated from Hardy-Weinberg equilibrium in three sheep breeds (P < 0.05). Further, AT genotype of SNP2 (INSL3 (A100T)) could significantly affect the estrus trait in Duolang sheep and Qira black sheep, and related to the litter size in Duolang sheep. The WNT2B significantly affected the estrus and litter size of Duolang sheep and Qira black sheep. INSL3 (A100T) and WNT2B (G126T) may be potential molecular markers for controlling seasonal reproductive trait in sheep.

Genetic Structure and Selection Signals for Extreme Environment Adaptation in Lop Sheep of Xinjiang

OBJECTIVE

Lop sheep species exhibit remarkable adaptability to desert pastures and extreme arid climates, demonstrating tolerance to rough feeding and high resistance to stress. However, little is known about the population genetic diversity of Lop sheep and the genetic mechanisms underlying their adaptability to extreme environments.

METHODS

Blood samples were collected from a total of 110 individuals comprising 80 Ruoqiang Lop sheep and 30 Yuli Lop sheep. A total of 110 Lop sheep were subjected to whole genome resequencing to analyze genetic diversity, population structure, and signatures of selection in both regions.

RESULTS

The genetic diversity of the Lop sheep population is substantial, and the degree of inbreeding is low. In comparison to the Lop sheep in Yuli County, the genetic diversity and linkage disequilibrium analysis results for the Lop sheep population in Ruoqiang County are slightly lower. Population structure analysis indicates that Ruoqiang and Yuli Lop sheep have differentiated into two independent groups. Using Yuli Lop sheep as the reference group, an analysis of the extreme environmental adaptability selection signal of Lop sheep was conducted. The FST and π ratio under the 1% threshold identified 1686 and 863 candidate genes, respectively, with their intersection yielding a total of 122 candidate genes. Functional annotation revealed that these genes are associated with various traits, including immune response (SLC12A2, FOXP1, PANX1, DYNLRB2, RAP1B, and SEMA4D), heat and cold resistance (DNAJC13, PLCB1, HIKESHI, and PITPNC1), desert adaptation (F13A1, PANX1, ST6GAL1, STXBP3, ACTN4, and ATP6V1A), and reproductive performance (RAP1B, RAB6A, PLCB1, and METTL15).

CONCLUSIONS

These research findings provide a theoretical foundation for understanding the survival and reproductive characteristics of Lop sheep in extreme environments, and they hold practical value for the conservation and utilization of Lop sheep genetic resources, as well as for genetic improvement efforts.

A New Function of the DRD1 Gene: GnRH Secretion Regulation in Sheep Hypothalamic Neurons

BACKGROUND

Dopamine (DA) is an important neurotransmitter that is widely present in the central nervous system. DA plays a crucial regulatory role in mammalian emotion, endocrine function, and reproduction through the activation of dopamine receptors. We compared the transcriptomes of hypothalamic tissues from Kazakh sheep during the nonbreeding season of anoestrus and during the nutrient-induced nonbreeding season of oestrus. Our research findings suggest that the dopamine receptor D1 (DRD1) gene may be a candidate gene for the regulation of sheep oestrus. However, the underlying mechanism through which DRD1 regulates sheep oestrus is still poorly understood.

METHODS

In the present study, the expression of DRD1 mRNA in the hypothalamus of oestrous Kazakh sheep was significantly greater than that in the anoestrous phase. Immunohistochemical staining revealed that DRD1 was more widely expressed in hypothalamic tissue and was more highly expressed during oestrus than during anoestrus. Hypothalamic neuron experiments further indicated that DRD1 affects the expression of GnRH through dopamine synapses and calcium signalling pathways.

RESULTS

moreover, the overexpression of the DRD1 gene promoted the secretion of GnRH, while knocking down the DRD1 gene reduced the secretion of GnRH.

CONCLUSIONS

The present study revealed that the DRD1 gene plays a crucial regulatory role in the secretion of the hormone GnRH in the hypothalamus of Kazakh sheep.

Integrating Genomic Selection and a Genome-Wide Association Study to Improve Days Open in Thai Dairy Holstein Cattle: A Comprehensive Genetic Analysis

Days open (DO) is a critical economic and reproductive trait that is commonly employed in genetic selection. Making improvements using conventional genetic techniques is exceedingly challenging. Therefore, new techniques are required to improve the accuracy of genetic selection using genomic data. This study examined the genetic approaches of traditional AIREML and single-step genomic AIREML (ssGAIREML) to assess genetic parameters and the accuracy of estimated breeding values while also investigating SNP regions associated with DO and identifying candidate genes through a genome-wide association study (GWAS). The dataset included 59415 DO records from 36368 Thai-Holstein crossbred cows and 882 genotyped animals. The cows were classified according to their Holstein genetic proportion (breed group, BG) as follows: BG1 (>93.7% Holstein genetics), BG2 (87.5% to 93.6% Holstein genetics), and BG3 (<87.5% Holstein genetics). AIREML was utilized to estimate genetic parameters and variance components. The results of this study reveal that the average DO values for BG1, BG2, and BG3 were 97.64, 97.25, and 96.23 days, respectively. The heritability values were estimated to be 0.02 and 0.03 for the traditional AIREML and ssGAIREML approaches, respectively. Depending on the dataset, the ssGAIREML method produced more accurate estimated breeding values than the traditional AIREML method, ranging from 40.5 to 45.6%. The highest values were found in the top 20% of the dam dataset. For the GWAS, we found 12 potential candidate genes (DYRK1A, CALCR, MIR489, MIR653, SLC36A1, GNA14, GNAQ, TRNAC-GCA, XYLB, ACVR2B, SLC22A14, and EXOC2) that are believed to have a significant influence on days open. In summary, the ssGAIREML method has the potential to enhance the accuracy and heritability of reproductive values compared to those obtained using conventional AIREML. Consequently, it is a viable alternative for transitioning from conventional methodologies to the ssGAIREML method in the breeding program for dairy cattle in Thailand. Moreover, the 12 identified potential candidate genes can be utilized in future studies to select markers for days open in regard to dairy cattle.

Population structure and selective signature analysis of local sheep breeds in Xinjiang, China based on high-density SNP chip

The frigid and droughty climate of Xinjiang in China has given rise to unique indigenous sheep breeds with robust adaptability and resistance. To investigate the genetic mechanism of adaptability of Xinjiang sheep to the local extreme environment, we conducted population genetic structure analyses for three native Xinjiang sheep breeds: Altay sheep (ALT), Bashbay Sheep (BSBC), and Duolang sheep (DLC), as well as two foreign sheep breeds: Suffolk and Dorset, using the Ovine Infinium HD SNP BeadChip(680 K). Our findings revealed distinct genetic and evolutionary histories between Xinjiang and foreign sheep breeds. Principal Component Analysis (PCA) and phylogenetic tree effectively differentiate these five sheep breeds based on their geographical origins, and the domestication level of Xinjiang sheep is comparatively lower than that of foreign sheep breeds. Furthermore, by utilizing three selective signature methods, namely Fixation Index (Fst), Cross Population Extended Haplotype Homozygosity Test (XP-EHH), and Nucleotide Diversity (π), we have successfully identified 22 potential candidate genes. Among these genes, there are TBXT, PDGFD, and VEGFA, which are closely related to tail type and lipid metabolism; VIL1, SLC11A1, and ZBTB46, which are associated with immune function; and candidate genes such as BNC1, HDAC1, and BMP5, which impact sheep reproductive traits. This study establishes a foundation for conserving and utilizing local sheep germplasm resources in Xinjiang and provides molecular insights into the genetic mechanisms governing sheep adaptation to extreme cold and arid environments.

Genetic Diversity, Selection Signatures, and Genome-Wide Association Study Identify Candidate Genes Related to Litter Size in Hu Sheep

Hu sheep is a renowned prolific local sheep breed in China, widely distributed across the country due to its excellent reproductive performance. Deciphering the molecular mechanisms underlying the high fecundity of Hu sheep is crucial for improving the litter size of ewes. In this study, we genotyped 830 female Hu sheep using the Illumina OvineSNP50 BeadChip and performed genetic diversity analysis, selection signature detection, and a genome-wide association study (GWAS) for litter size. Our results revealed that the Hu sheep population exhibits relatively high genetic diversity. A total of 4927 runs of homozygosity (ROH) segments were detected, with the majority (74.73%) being short in length. Different genomic inbreeding coefficients (FROH, FHOM, FGRM, and FUNI) ranged from -0.0060 to 0.0126, showing low levels of inbreeding in this population. Additionally, we identified 91 candidate genomic regions through three complementary selection signature methods, including ROH, composite likelihood ratio (CLR), and integrated haplotype score (iHS), and annotated 189 protein-coding genes. Moreover, we observed two significant SNPs related to the litter size of Hu sheep using GWAS analysis based on a repeatability model. Integrating the selection signatures and the GWAS results, we identified 15 candidate genes associated with litter size, among which BMPR1B and UNC5C were particularly noteworthy. These findings provide valuable insights for improving the reproductive performance and breeding of high-fecundity lines of Hu sheep.

The genetic characterization of germplasm and identification of the litter size trait associated candidate genes in Dexin mutton and fine-wool sheep

Xinjiang is a major province of sheep breeding in China, which plays an important role in meeting people's needs for meat products, increasing farmers' income and sustainable development of animal husbandry. However, the genetic differentiation relationship between breeds was not clear, and most sheep had low fecundity, which seriously restricted the efficient development of sheep industry. Therefore, this study used the whole genome resequencing to detect the genetic variation of Dexin mutton and fine-wool sheep, explored the selected regions and important genes of the litter size traits, analyzed the genetic mechanism of reproductive traits, and provided new insights for the high fecundity breeding of sheep. A total of 5,236.338 G genome data and 35,884,037 SNPs were obtained. Furthermore, we identified 39 selection signals spanning candidate genes, 99 genes were significantly associated related to growth, reproduction and immunity, among which, BRIP1, BMPR1B, BMP4, NGF, etc. genes, and MAKP signaling pathway, Fanconi anemia pathway and Thyroid hormone signaling pathway and other signaling pathways were significantly correlated with litter size trait. Among them, we identified NGF, TrKA and BRIP1 genes was the important genes for sheep litter size traits and the mutation frequencies of 9 SNPs in BRIP1 gene were significantly different in domestic sheep in the world. The research provided new insights for the breeding of self-cultivated meat fine-wool sheep.

Characterization and analysis of transcriptomes of multiple tissues from estrus and diestrus in pigs

A comprehensive understanding of the complex regulatory mechanisms governing estrus and ovulation across multiple tissues in mammals is imperative to improve the reproductive performance of livestock and mitigate ovulation-related disorders in humans. To comprehensively elucidate the regulatory landscape, we analyzed the transcriptome of protein-coding genes and long intergenic non-coding RNAs (lincRNAs) in 58 samples (including the hypothalamus, pituitary, ovary, vagina, and vulva) derived from European Large White gilts and Chinese Mi gilts during estrus and diestrus. We constructed an intricate regulatory network encompassing 358 hub genes across the five examined tissues. Furthermore, our investigation identified 85 differentially expressed lincRNAs that are predicted to target 230 genes associated with critical functions including behavior, receptors, and apoptosis. Importantly, we found that vital components of estrus and ovulation events involve "Apoptosis" pathway in the hypothalamus, "Autophagy" in the ovary, as well as "Hypoxia" and "Angiogenesis" in the vagina and vulva. We have identified several differentially expressed transcription factors (TFs), such as SPI1 and HES2, which regulate these pathways. SPI1 may suppress transcription in the autophagy pathway, promoting apoptosis and inhibiting the proliferation of ovarian granulosa cells. Our study provides the most comprehensive transcriptional profiling information related to estrus and ovulation events.

Transcriptome Analysis Reveals Differentially Expressed circRNAs Associated with Fecundity in Small-Tail Han Sheep Thyroid with Different FecB Genotypes

Litter size is an economically important trait in sheep, and it is a complex trait controlled by multiple genes in multiple organs. Among them, the regulation of lamb number trait by the thyroid gland is a very important part. However, the molecular mechanisms of the thyroid gland in sheep reproduction remain unclear. Here, RNA-seq was used to detect transcriptome expression patterns in the thyroid gland between follicular phase (FP) and luteal phase (LP) in FecB BB (MM) and FecB ++ (ww) STH sheep, respectively, and to identify differentially expressed circRNAs (DECs) associated with reproduction. Bioinformatic analysis of the source genes of these DECs revealed that they can be enriched in multiple signaling pathways involved in the reproductive process of animals. We found that the source genes of these DECs, such as GNAQ, VEGFC, MAPK1, STAT1, and HSD17B7, may play important roles in the reproductive process of animals. To better understand the function of these DECs, we constructed circRNA-miRNA co-expression networks. Dual luciferase reporter assays suggested that a ceRNA regulatory mechanism between circ_0003259-oar-miR-133-TXLNA and circ_0012128-oar-miR-370-3p-FGFR1 may hold. All of these DEC expression profiles in the thyroid gland provide a novel resource for elucidating the regulatory mechanisms underlying STH sheep prolificacy.

Photoperiod Induces the Epigenetic Change of the GNAQ Gene in OVX+E2 Ewes

GNAQ, a member of the alpha subunit encoding the q-like G protein, is a critical gene in cell signaling, and multiple studies have shown that upregulation of GNAQ gene expression ultimately inhibits the proliferation of gonadotropin-releasing hormone (GnRH) neurons and GnRH secretion, and ultimately affects mammalian reproduction. Photoperiod is a key inducer which plays an important role in gene expression regulation by affecting epigenetic modification. However, fewer studies have confirmed how photoperiod induces epigenetic modifications of the GNAQ gene. In this study, we examined the expression and epigenetic changes of GNAQ in the hypothalamus in ovariectomized and estradiol-treated (OVX+E2) sheep under three photoperiod treatments (short photoperiod treatment for 42 days, SP42; long photoperiod treatment for 42 days, LP42; 42 days of short photoperiod followed by 42 days of long photoperiod, SP-LP42). The results showed that the expression of GNAQ was significantly higher in SP-LP42 than in SP42 and LP42 (p < 0.05). Whole genome methylation sequencing (WGBS) results showed that there are multiple differentially methylated regions (DMRs) and loci between different groups of GNAQ. Among them, the DNA methylation level of DMRs at the CpG1 locus in SP42 was significantly higher than that of SP-LP42 (p < 0.01). Subsequently, we confirmed that the core promoter region of the GNAQ gene was located with 1100 to 1500 bp upstream, and the DNA methylation level of all eight CpG sites in SP42 was significantly higher than those in LP42 (p < 0.01), and significantly higher than those in SP-LP42 (p < 0.01), except site 2 and site 4 in the first sequencing fragment (p < 0.05) in the core promoter region. The expression of acetylated GNAQ histone H3 was significantly higher than that of the control group under three different photoperiods (p < 0.01); the acetylation level of sheep hypothalamic GNAQ genomic protein H3 was significantly lower under SP42 than under SP-LP42 (p < 0.05). This suggests that acetylated histone H3 binds to the core promoter region of the GNAQ gene, implying that GNAQ is epigenetically regulated by photoperiod through histone acetylation. In summary, the results suggest that photoperiod can induce DNA methylation in the core promoter region and histone acetylation in the promoter region of the GNAQ gene, and hypothesize that the two may be key factors in regulating the differential expression of GNAQ under different photoperiods, thus regulating the hypothalamus-pituitary-gonadal axis (HPGA) through the seasonal estrus in sheep. The results of this study will provide some new information to understand the function of epigenetic modifications in reproduction in sheep.

Whole-genome resequencing of the native sheep provides insights into the microevolution and identifies genes associated with reproduction traits

BACKGROUND

Sheep genomes undergo numerous genes losses, gains and mutation that generates genome variability among breeds of the same species after long time natural and artificial selection. However, the microevolution of native sheep in northwest China remains elusive. Our aim was to compare the genomes and relevant reproductive traits of four sheep breeds from different climatic environments, to unveil the selection challenges that this species cope with, and the microevolutionary differences in sheep genomes. Here, we resequenced the genomes of 4 representative sheep breeds in northwest China, including Kazakh sheep and Duolang sheep of native breeds, and Hu sheep and Suffolk sheep of exotic breeds with different reproductive characteristics.

RESULTS

We found that these four breeds had a similar expansion experience from ~ 10,000 to 1,000,000 years ago. In the past 10,000 years, the selection intensity of the four breeds was inconsistent, resulting in differences in reproductive traits. We explored the sheep variome and selection signatures by F_ST and θπ. The genomic regions containing genes associated with different reproductive traits that may be potential targets for breeding and selection were detected. Furthermore, non-synonymous mutations in a set of plausible candidate genes and significant differences in their allele frequency distributions across breeds with different reproductive characteristics were found. We identified PAK1, CYP19A1 and PER1 as a likely causal gene for seasonal reproduction in native sheep through qPCR, Western blot and ELISA analyses. Also, the haplotype frequencies of 3 tested gene regions related to reproduction were significantly different among four sheep breeds.

CONCLUSIONS

Our results provide insights into the microevolution of native sheep and valuable genomic information for identifying genes associated with important reproductive traits in sheep.

Sleep Deprivation and Central Appetite Regulation

Research shows that reduced sleep duration is related to an increased risk of obesity. The relationship between sleep deprivation and obesity, type 2 diabetes, and other chronic diseases may be related to the imbalance of appetite regulation. To comprehensively illustrate the specific relationship between sleep deprivation and appetite regulation, this review introduces the pathophysiology of sleep deprivation, the research cutting edge of animal models, and the central regulatory mechanism of appetite under sleep deprivation. This paper summarizes the changes in appetite-related hormones orexin, ghrelin, leptin, and insulin secretion caused by long-term sleep deprivation based on the epidemiology data and animal studies that have established sleep deprivation models. Moreover, this review analyzes the potential mechanism of associations between appetite regulation and sleep deprivation, providing more clues on further studies and new strategies to access obesity and metabolic disease.

Identification and expression analysis of zebrafish gnaq in the hypothalamic–Pituitary–Gonadal axis

The G proteins have emerged as essential molecular switches in a wide variety of signal transduction pathways. Gαq, encoded by G protein subunit alpha q (gnaq), is a member of the G proteins and participates in regulating important biological activities in mammals; however, its function and regulatory mechanism in teleost remain largely unclear. In the current study, we cloned the cDNA of gnaq from zebrafish (Danio rerio) and investigated the expression characteristics of Gαq/gnaq in reproductive tissues. RT-PCR and WISH analyses showed that gnaq was widely expressed in zebrafish tissues, with high expression in the brain, olfactory brain, and hypothalamus. During the embryonic development stage, the gnaq was mainly distributed in the hypothalamus after 72 h post-fertilization. In addition, immunohistochemistry analysis revealed that the Gαq protein was highly expressed in the diffuse nucleus of the inferior hypothalamic lobe (DIL), ventral zone of the periventricular hypothalamus (Hv), and caudal zone of the periventricular hypothalamus (Hc) in adult zebrafish. Furthermore, in the gonads, the Gαq protein was found in oocytes of all stages, except spermatids. Lastly, the gnaq mRNA exhibited relatively low expression in gonads on Day 4 during the reproductive cycle, while increasing drastically in the hypothalamus and pituitary afterward. Altogether, our results suggest that gnaq/Gαq might be important in fish reproduction.

Genetic Basis of Sexual Maturation Heterosis: Insights From Ovary lncRNA and mRNA Repertoire in Chicken

Sexual maturation is fundamental to the reproduction and production performance, heterosis of which has been widely used in animal crossbreeding. However, the underlying mechanism have long remained elusive, despite its profound biological and agricultural significance. In the current study, the reciprocal crossing between White Leghorns and Beijing You chickens were performed to measure the sexual maturation heterosis, and the ovary lncRNAs and mRNAs of purebreds and crossbreeds were profiled to illustrate molecular mechanism of heterosis. Heterosis larger than 20% was found for pubic space and oviduct length, whereas age at first egg showed negative heterosis in both crossbreeds. We identified 1170 known lncRNAs and 1994 putative lncRNAs in chicken ovary using a stringent pipeline. Gene expression pattern showed that nonadditivity was predominant, and the proportion of nonadditive lncRNAs and genes was similar between two crossbreeds, ranging from 44.24% to 49.15%. A total of 200 lncRNAs and 682 genes were shared by two crossbreeds, respectively. GO and KEGG analysis showed that the common genes were significantly enriched in the cell cycle, animal organ development, gonad development, ECM-receptor interaction, calcium signaling pathway and GnRH signaling pathway. Weighted gene co-expression network analysis (WGCNA) identified that 7 out of 20 co-expressed lncRNA-mRNA modules significantly correlated with oviduct length and pubic space. Interestingly, genes harbored in seven modules were also enriched in the similar biological process and pathways, in which nonadditive lncRNAs, such as MSTRG.17017.1 and MSTRG.6475.20, were strongly associated with nonadditive genes, such as CACNA1C and TGFB1 to affect gonad development and GnRH signaling pathway, respectively. Moreover, the results of real-time quantitative PCR (RT-qPCR) correlated well with the transcriptome data. Integrated with positive heterosis of serum GnRH and melatonin content detected in crossbreeds, we speculated that nonadditive genes involved in the GnRH signaling pathway elevated the gonad development, leading to the sexual maturation heterosis. We characterized a systematic landscape of ovary lncRNAs and mRNAs related to sexual maturation heterosis in chicken. The quantitative exploration of hybrid transcriptome changes lays foundation for genetic improvement of sexual maturation traits and provides insights into endocrine control of sexual maturation.