Gene expression profiling ofcorpus luteumreveals the importance of immune system during early pregnancy in domestic sheep

Abstract

17The majority of pregnancy loss in ruminants occurs during the preimplantation stage, which is thus 18 the most critical period determining reproductive success. While ovulation rate is the major 19 determinant of litter size in sheep, interactions among the conceptus, corpus luteum and endometrium 20 are essential for pregnancy success. To evaluate the role of reproductive tract function in sheep 21 fertility, we performed a comparative transcriptome study by sequencing total RNA (mRNA and 22 miRNA) from corpus luteum (CL) and endometrium tissues collected during the preimplantation 23 stage of pregnancy in Finnsheep, Texel and F1 crosses. A total of 21,287 genes and 599 miRNAs 24were expressed in our dataset. Ten out of the top 25 most highly expressed genes were shared across 25 tissues, indicating the complementary functions of the CL and endometrium. Moreover, highly 26 expressed autosomal genes in the endometrium and CL were associated with biological processes 27 such as progesterone formation (STAR and HSD3B1) in the CL and facilitation of maternal 28 recognition of pregnancy, trophoblast elongation and implantation (LGALS15, CST3, CST6, and 29 EEF1A1) in the endometrium. In the CL, a group of sialic acid-binding immunoglobulin (Ig)-like 30 lectins (Siglecs), solute carriers (SLC13A5, SLC15A2, SLC44A5) and chemokines (CCL5, CXCL13, 31 CXCL9) were upregulated in Finnsheep, while several multidrug resistance-associated proteins 32(MRPs) were upregulated in Texel ewes. We also identified a novel ERV gene located in a reduced 33FecL locus that is associated with sheep prolificacy and is upregulated in prolific Finnsheep. 34Moreover, we report, for the first time in any species, several genes that are active in the CL during 35 early pregnancy (including SIGLEC13, SIGLEC14, SIGLEC6, MRP4, and CA5A). Importantly, 36 functional analysis of differentially expressed genes suggested that Finnsheep have a better immune 37

Genome-wide scans identify known and novel regions associated with prolificacy and reproduction traits in a sub-Saharan African indigenous sheep (Ovis aries)

“…Functional enrichment analysis using the highest classification stringency in DAVID 6.8 revealed four enriched clusters with genes linked to immune functions being overrepresented, a result which was replicated by STRING. The importance of the immune system in reproduction in sheep has recently been reported (Pokharel et al 2019). Following arguments advanced in other studies that found an over-representation of immune-related genes in the genomes of tropically adapted livestock (Xu et al 2015; Bahbahani et al 2017; Mwacharo et al 2017), it can also be argued that selection has enhanced adaptive immune response to tropical infections in the genomes of Bonga sheep.…”

Genomic regions associated with resistance to gastrointestinal parasites in Australian Merino sheep

“…Among these, several are involved in the mechanisms of innate and adaptive immunity in mammals, such as HERC2 and CYFIP1 that are also involved in cytokine signaling [38,40]. The PDLIM2 gene has been associated in transcriptomic studies with the immune system and reproduction in sheep [41]. PTPN18 is involved in the B-cell receptor signaling pathway, being involved in differentiation, proliferation and immunoglobulin (Ig) production [38], while other reports relate it to pigmentation in Merino sheep [42].…”

Whole genome re-sequencing reveals artificial and natural selection for milk traits in East Friesian sheep

“…The candidate genes B4GALNT4 ( 33 ) involved in lactose synthesis, RCOR1 ( 34 ) related to milk yield and SH3D19 related to lactation process in sheep were also identified ( 35 ). In addition, our results contain a large number of candidate genes related to production traits, such as reproductive trait candidates: FSIP2 ( 17 ), CD226 ( 36 ), SLC44A5 ( 37 ), GPR83 ( 38 ), SUN5 ( 39 ), GPR173 ( 40 ), LHX8 ( 41 ), SIRT3 ( 42 ), FGF16 ( 43 ), POU3F4 ( 44 ), these genes affect reproductive traits by influencing days of estrus, luteal gland, participating in reproductive regulation, and hypothalamic-pituitary-gonadal axis regulation. For example, the candidate genes for wool traits: RALY ( 45 ), GLI2 ( 46 ), TXNRD3 ( 47 ), EIF2S2 ( 45 ), IRF2BP2 ( 48 ), etc.…”