964
Changes in the cattle cervical transcriptome between estrus and luteal phase
During the periestrous phase the cow cervix undergoes changes associated with hormonal phases that affect the secretions. The cervical mucus fluctuates from fluid and abundant, allowing the sperm transport at estrus, to dense and thick, creating a barrier that minimize pathogen colonization and infection during pregnancy or luteal phase. The corresponding changes in the transcriptome have not be fully characterized. The objective of this study was to identify the genes that are differentially expressed between the estrus (n=4) and luteal (7 days postestrus, n=5) phases in the cervical tissue of synchronized beef heifers. An RNA-Seq platform (Illumina Genome Analyzer II) was used to identify and quantify the transcripts. Single-end reads were mapped to the Bos taurus reference genome (Baylor Btau_4.6.1/bos Tau7). In total, 14,419 transcripts from 13,822 genes were tested and 1,163 transcripts from 1,150 genes were differentially expressed between the luteal and estrus phases (False Discovery Rate adjusted P-value < 0.05). Among these, angiotensinogen (AGT) and potassium voltage-gated channel, subfamily F, member 1 (KCNF1) were over-expressed while cartilage oligomeric matrix protein (COMP) and chloride channel accessory 1 (CLCA1) were under-expressed in the luteal relative to the estrus phase. These results are consistent with known gene functions. AGT produces the enzyme angiotensin II that has been associated with the corpus luteum. KCNF1 regulates the epithelial electrolyte transport and COMP plays a role in cell proliferation, apoptosis, and regulation of cell movement and attachment. Also, the activity of CLCA1 decreases during the luteal phase when mucus thickens. Functional analysis of the differentially expressed genes using DAVID identified six category clusters (enrichment score > 3 equivalent to average category P-value < 0.001). These categories included cartilage development and condensation, inflammatory responses, defense responses, and sterol-cholesterol biosynthetic. 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 penetrability of the cervix.
Keywords: RNA-seq, cervix, cow