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Changes in the cattle cervical transcriptome between estrus and metestrus
The cow’s reproductive tract undergoes changes during the periestrous period that enable sperm access through the cervix to the lumen of the uterus while minimizing pathogen colonization and infection. The objective of this study was to identify the genes that are differentially expressed between the estrus (n=4) and metestrus (48 hr postestrus, n=5) periods in the cervical tissue of synchronized beef heifers. RNA-Seq was used to measure transcript abundance with the Illumina Genome Analyzer II platform. Single-end reads were mapped to the Bos taurus reference genome (Baylor Btau_4.6.1/bos Tau7). In total, 14,420 transcripts from 13,823 genes were tested and 1,161 transcripts from 1,154 genes were found to be differentially expressed (False Discovery Rate adjusted P-value < 0.05). Among these, TAP tracheal antimicrobial peptide (TAP) and GABRP gamma-aminobutyric acid (GABA) A receptor, pi were over-expressed while PADI1 peptidyl arginine deiminase, type I and TH tyrosine hydroxylase were under-expressed in metestrus relative to estrus. TAP produced by mucosal epithelial cells of cattle has been associated with defense against bacterial pathogens. In turn, GABA has been associated with uterus contractility. Functional analysis of the differentially expressed genes using DAVID identified seven category clusters (enrichment score > 3 equivalent to average category P-value < 0.001). These categories included sterol, cholesterol, and lipid biosynthetic, inflammatory response, tissue development and cell differentiation. These functional categories suggest that changes during the estrus cycle are associated with changes in molecular pathways that in turn may affect the morphology, function and antimicrobial capability of the cervix.
Keywords: RNA-seq, cervix, cow