Bovine Genome Analysis to Unravel the Location and Feature of Target Sites of RNA-Guided Hyperactivated Recombinase Gin with Spacer Length Six

Background: Programmable nucleases are very promising tools of genome editing (GE), but they suffer from limitations including potential risk of genotoxicity which led to the exploration of safer approach of GE based on RNA-guided recombinase (RGR) platform. RNA-guided recombinase (RGR) platform operates on a typical recognition or target site comprised of the minimal pseudo-core recombinase site, a 5 to 6-base pair spacer flanking it and whole this central region is flanked by two guide RNA-specified DNA sequences or Cas9 binding sites followed by protospacer adjacent motifs (PAMs). Methods: The current study focuses on analysis of entire cattle genome to prepare a detailed map of target sites for RNA-guided hyperactivated recombinase Gin with spacer length six. For this, chromosome wise whole genomic sequence data was retrieved from Ensembl. After that search pattern for recombinase Gin with spacer length six was designed. By using this search pattern, RGR target sites were located by using dreg program of Emboss package. Result: Total number of RGR target sites identified in bovine genome for recombinase Gin was 677 with spacer length six. It was also investigated that whether these RGR target sites are present with in any gene or not and it was found that RGR target sites lies in both genic and intergenic region. Besides this, description of genes in context with these target sites was identified.

Multipopulational transcriptome analysis of post-weaned beef cattle at arrival further validates candidate biomarkers for predicting clinical bovine respiratory disease

Bovine respiratory disease (BRD) remains the leading infectious disease in post-weaned beef cattle. The objective of this investigation was to contrast the at-arrival blood transcriptomes from cattle derived from two distinct populations that developed BRD in the 28 days following arrival versus cattle that did not. Forty-eight blood samples from two populations were selected for mRNA sequencing based on even distribution of development (n = 24) or lack of (n = 24) clinical BRD within 28 days following arrival; cattle which developed BRD were further stratified into BRD severity cohorts based on frequency of antimicrobial treatment: treated once (treated_1) or treated twice or more and/or died (treated_2+). Sequenced reads (~ 50 M/sample, 150 bp paired-end) were aligned to the ARS-UCD1.2 bovine genome assembly. One hundred and thirty-two unique differentially expressed genes (DEGs) were identified between groups stratified by disease severity (healthy, n = 24; treated_1, n = 13; treated_2+, n = 11) with edgeR (FDR ≤ 0.05). Differentially expressed genes in treated_1 relative to both healthy and treated_2+ were predicted to increase neutrophil activation, cellular cornification/keratinization, and antimicrobial peptide production. Differentially expressed genes in treated_2+ relative to both healthy and treated_1 were predicted to increase alternative complement activation, decrease leukocyte activity, and increase nitric oxide production. Receiver operating characteristic (ROC) curves generated from expression data for six DEGs identified in our current and previous studies (MARCO, CFB, MCF2L, ALOX15, LOC100335828 (aka CD200R1), and SLC18A2) demonstrated good-to-excellent (AUC: 0.800–0.899; ≥ 0.900) predictability for classifying disease occurrence and severity. This investigation identifies candidate biomarkers and functional mechanisms in at arrival blood that predicted development and severity of BRD.

Transcriptome analysis reveals disruption of circadian rhythms in late gestation dairy cows may increase risk for fatty liver and reduced mammary remodeling

Circadian disruption increased insulin resistance and decreased mammary development in late gestation, non-lactating (dry) cows. The objective was to measure the effect of circadian disruption on transcriptomes of the liver and mammary gland. At 35 d before expected calving (BEC) multiparous dry cows were assigned to either control (CON) or phase-shifted treatments (PS). CON was exposed to 16 h light and 8 h of dark. PS was exposed to 16 h light to 8 h dark, but phase of the light-dark cycle was shifted 6 h every 3 d. On d 21 BEC, liver and mammary were biopsied. RNA was isolated (n=6 CON, n=6 PS per tissue), libraries prepared and sequenced using paired end reads. Reads mapping to bovine genome averaged 27 M ± 2 M, and aligned to 14,222 protein coding genes in liver and 15,480 in mammary analysis. In the liver, 834 genes, and in the mammary gland, 862 genes were different (nominal P < 0.05) between PS and CON. In the liver, genes upregulated in PS functioned in cholesterol biosynthesis, endoplasmic reticulum stress, wound healing, and inflammation. Genes downregulated in liver function in cholesterol efflux. In the mammary gland, genes upregulated functioned in mRNA processing and transcription, downregulated genes encoded extracellular matrix proteins and proteases, cathepsins and lysosomal proteases, lipid transporters and regulated oxidative phosphorylation. Increased cholesterol synthesis and decreased efflux suggests circadian disruption potentially increases the risk of fatty liver in cows. Decreased remodeling and lipid transport in mammary may decrease milk production capacity during lactation.

Anchoring the CerEla1.0 Genome Assembly to Red Deer (Cervus elaphus) and Cattle (Bos taurus) Chromosomes and Specification of Evolutionary Chromosome Rearrangements in Cervidae

The family Cervidae groups a range of species with an increasing economic significance. Their karyotypes share 35 evolutionary conserved chromosomal segments with cattle (Bos taurus). Recent publication of the annotated red deer (Cervus elaphus) whole genome assembly (CerEla1.0) has provided a basis for advanced genetic studies. In this study, we compared the red deer CerEla1.0 and bovine ARS-UCD1.2 genome assembly and used fluorescence in situ hybridization with bovine BAC probes to verify the homology between bovine and deer chromosomes, determined the centromere-telomere orientation of the CerEla1.0 C-scaffolds and specified positions of the cervid evolutionary chromosome breakpoints. In addition, we revealed several incongruences between the current deer and bovine genome assemblies that were shown to be caused by errors in the CerEla1.0 assembly. Finally, we verified the centromere-to-centromere orientation of evolutionarily fused chromosomes in seven additional deer species, giving a support to previous studies on their chromosome evolution.

Amplification, copy number variation, expression and association of non-synonymous SNP of bovine beta-defensin 129 gene with distinct fertility of cattle bull

Background: The male reproductive specific class-A β-defensins are adsorbed on sperm surface and enrich sperm functioning thus considered vital for maintaining male fertility. The primate DEFB129 play role in sperm maturation, motility, and fertilization but its contribution to bovine fertility is still unexplored.Method: RLM-RACE and RT-qPCR approaches were used to characterize and expression analysis of Indian cattle BBD129 gene. The polymorphism analysis of the BBD129 gene was done by PCR, sequencing, and absolute RT-qPCR on sperm gDNA from distinct fertility cattle bulls. Bioinformatic analysis was performed to understand the structural and functional implications of SNP on BBD129 protein.Results: The complete coding sequence of the BBD129 gene consists of 582 bp mRNA including UTRs and conserves all beta-defensin-like characteristics. Sequencing results revealed two conserved non-synonymous T169G (rs378737321, S57A) and A329G (rs383285978, N110S) SNPs in the functional protein-coding exon. Based on SNP position and linkage, BBD129 gene haplotypes were categorized into four groups: TA haplotype (169T & 329A), GA haplotype (T169G polymorphism), TG haplotype (A329G polymorphism), and GG haplotype (when T169G & A329G polymorphisms present together). The frequencies distributions of BBD129 haplotypes in the high fertile group (n=105 clones) were: TA (71.42%), GA (1.90%), TG (2.8%), and GG (24.76%), while in the low fertile group of bulls, the frequencies distributions of observed BBD129 haplotypes (n=149 clones) were: TA (36.24%), GA (0%), TG (2.68%), and GG (61.07%). The distributions of TA haplotype were majorly distributed in bulls with a high conception rate (P=0.5256) while double mutated GG haplotype was significantly more abundant in bulls with a lower conception rate (P=0.0001). BBD129 exist as a single-copy gene in the bovine genome and found higher expression in the corpus-epididymis region. Bioinformatic analyses found nsSNPs as neutral and non-deleterious but their structural-distorter could result in altered mRNA secondary structure, protein conformations decreased protein stability, and compromised biological functionalities. The polymorphisms resulted in altered O-glycosylations (deletion S57A and insertion N110S) and an increase in phosphorylations (52T-Threonine and 110S-Serine) post-translational-modifications.Conclusion: BBD129 gene polymorphism could be associated with the fertility performance of cattle bulls.

Amplification, Copy Number Variation, Expression and Association of Non-synonymous SNP of Bovine Beta-defensin 129 Gene With Distinct Fertility of Cattle Bull

BackgroundThe male reproductive specific class-A β-defensins are adsorbed on sperm surface and enrich sperm functioning thus considered vital for maintaining male fertility. The primate DEFB129 play role in sperm maturation, motility, and fertilization but its contribution to bovine fertility is still unexplored. MethodRLM-RACE and RT-qPCR approaches were used to characterize and expression analysis of Indian cattle BBD129 gene. The polymorphism analysis of the BBD129 gene was done by PCR, sequencing, and absolute RT-qPCR on sperm gDNA from distinct fertility cattle bulls. Bioinformatic analysis was performed to understand the structural and functional implications of SNP on BBD129 protein. ResultsThe complete coding sequence of the BBD129 gene consists of 582 bp mRNA including UTRs and conserves all beta-defensin-like characteristics. Sequencing results revealed two conserved non-synonymous T169G (rs378737321, S57A) and A329G (rs383285978, N110S) SNPs in the functional protein-coding exon. Based on SNP position and linkage, BBD129 gene haplotypes were categorized into four groups: TA haplotype (169T & 329A), GA haplotype (T169G polymorphism), TG haplotype (A329G polymorphism), and GG haplotype (when T169G & A329G polymorphisms present together). The frequencies distributions of BBD129 haplotypes in the high fertile group (n=105 clones) were: TA (71.42%), GA (1.90%), TG (2.8%), and GG (24.76%), while in the low fertile group of bulls, the frequencies distributions of observed BBD129 haplotypes (n=149 clones) were: TA (36.24%), GA (0%), TG (2.68%), and GG (61.07%). The distributions of TA haplotype were majorly distributed in bulls with a high conception rate (P=0.5256) while double mutated GG haplotype was significantly more abundant in bulls with a lower conception rate (P=0.0001). BBD129 exist as a single-copy gene in the bovine genome and found higher expression in the corpus-epididymis region. Bioinformatic analyses found nsSNPs as neutral and non-deleterious but their structural-distorter could result in altered mRNA secondary structure, protein conformations decreased protein stability, and compromised biological functionalities. The polymorphisms resulted in altered O-glycosylations (deletion S57A and insertion N110S) and an increase in phosphorylations (52T-Threonine and 110S-Serine) post-translational-modifications. ConclusionBBD129 gene polymorphism could be associated with the fertility performance of cattle bulls.

Identification of Genomic Regions Influencing N-Metabolism and N-Excretion in Lactating Holstein- Friesians

Excreted nitrogen (N) of dairy cows contribute to environmental eutrophication. The main N-excretory metabolite of dairy cows is urea, which is synthesized as a result of N-metabolization in the liver and is excreted via milk and urine. Genetic variation in milk urea (MU) has been postulated but the complex physiology behind the trait as well as the tremendous diversity of processes regulating the N-metabolism impede the consistent determination of causal regions in the bovine genome. In order to map the genetic determinants affecting N-excretion, MU and eight other N-excretory metabolites in milk and urine were assessed in a genome-wide association study. Therefore phenotypes of 371 Holstein- Friesians were obtained in a trial on a dairy farm under near commercial conditions. Genotype data comprised SNP information of the Bovine 50K MD Genome chip (45,613 SNPs). Significantly associated genomic regions for MU concentration revealed GJA1 (BTA 9), RXFP1, and FRY1 (both BTA 12) as putative candidates. For milk urea yield (MUY) a promising QTL on BTA 17 including SH3D19 emerged, whereas RCAN2, CLIC5, ENPP4, and ENPP5 (BTA 23) are suggested to influence urinary urea concentration. Minor N-fractions in milk (MN) may be regulated by ELF2 and SLC7A11 (BTA 17), whilst ITPR2 and MYBPC1 (BTA 5), STIM2 (BTA 6), SGCD (BTA 7), SLC6A2 (BTA 18), TMCC2 and MFSD4A (BTA 16) are suggested to have an impact on various non-urea-N (NUN) fractions excreted via urine. Our results highlight genomic regions and candidate genes for N-excretory metabolites and provide a deeper insight into the predisposed component to regulate the N-metabolism in dairy cows.

The Bovine Foot Skin Microbiota is Associated with Host Genotype and the Development of Infectious Digital Dermatitis Lesions

Bovine Digital Dermatitis (BDD) is a prevalent infectious disease, causing painful foot skin lesions and lameness in cattle. The polymicrobial nature of this disease has led to the hypothesis that the foot skin microbiota may be associated with occurrence and progression of lesions. We describe herein the bovine foot skin microbiota using 16S rRNA gene amplicon and shotgun metagenomic sequencing on samples from 259 dairy cows from three UK dairy farms. We show differences in the foot skin microbiome profiles of clinically healthy animals that were associated with subsequent development of BDD. We also present the first co-occurrence analysis of the bovine foot skin microbiome showing ecological relationships among bacterial species. Taxonomical and functional differences together with alterations in ecological interactions between bacteria in the normal foot skin microbiome may predispose an animal to develop BDD lesions. Using genome-wide association and regional heritability mapping approaches, we provide first evidence for interactions between host genotype and the foot skin microbiota profiles. We show the existence of genetic variation in the relative abundance of Treponema spp. and Peptoclostridium spp. and identify regions in the bovine genome that explain a significant proportion of this variation.

Putative Causal Variants Are Enriched in Annotated Functional Regions From Six Bovine Tissues

Genetic variants which affect complex traits (causal variants) are thought to be found in functional regions of the genome. Identifying causal variants would be useful for predicting complex trait phenotypes in dairy cows, however, functional regions are poorly annotated in the bovine genome. Functional regions can be identified on a genome-wide scale by assaying for post-translational modifications to histone proteins (histone modifications) and proteins interacting with the genome (e.g., transcription factors) using a method called Chromatin immunoprecipitation followed by sequencing (ChIP-seq). In this study ChIP-seq was performed to find functional regions in the bovine genome by assaying for four histone modifications (H3K4Me1, H3K4Me3, H3K27ac, and H3K27Me3) and one transcription factor (CTCF) in 6 tissues (heart, kidney, liver, lung, mammary and spleen) from 2 to 3 lactating dairy cows. Eighty-six ChIP-seq samples were generated in this study, identifying millions of functional regions in the bovine genome. Combinations of histone modifications and CTCF were found using ChromHMM and annotated by comparing with active and inactive genes across the genome. Functional marks differed between tissues highlighting areas which might be particularly important to tissue-specific regulation. Supporting the cis-regulatory role of functional regions, the read counts in some ChIP peaks correlated with nearby gene expression. The functional regions identified in this study were enriched for putative causal variants as seen in other species. Interestingly, regions which correlated with gene expression were particularly enriched for potential causal variants. This supports the hypothesis that complex traits are regulated by variants that alter gene expression. This study provides one of the largest ChIP-seq annotation resources in cattle including, for the first time, in the mammary gland of lactating cows. By linking regulatory regions to expression QTL and trait QTL we demonstrate a new strategy for identifying causal variants in cattle.

Multipopulational Transcriptome Analysis of Post-Weaned Beef Cattle at Arrival Further Validates Candidate Biomarkers for Predicting Clinical Bovine Respiratory Disease

Bovine respiratory disease (BRD) remains the leading infectious disease in post-weaned beef cattle. The objective of this investigation was to contrast the at-arrival blood transcriptomes from cattle derived from two distinct populations that developed BRD in the 28 days following arrival versus cattle that did not. 48 blood samples from two populations were selected for mRNA sequencing based on even distribution of development (n=24) or lack of (n=24) clinical BRD within 28 days following arrival. Sequenced reads (~50M/sample, 150 bp paired-end) were aligned to the ARS-UCD1.2 bovine genome assembly. 132 unique DEGs were identified between groups stratified by disease severity (healthy, n=24; treated_1, n=13; treated_2+, n=11) with edgeR (FDR < 0.05). DEGs in treated_1 relative to both healthy and treated_2+ were predicted to increase neutrophil activation, cellular cornification/keratinization, and antimicrobial peptide production. DEGs in treated_2+ relative to both healthy and treated_1 were predicted to increase alternative complement activation, decrease leukocyte activity, and increase nitric oxide production. Receiver operating characteristic (ROC) curves generated from expression data for six DEGs identified in our current and previous studies (MARCO, CFB, MCF2L, ALOX15, LOC100335828 (aka CD200R1), and SLC18A2) demonstrated good-to-excellent predictability for classifying disease occurrence and severity. This investigation identifies candidate biomarkers and functional mechanisms in at arrival blood that predicted development and severity of BRD.