Transcriptome Profiling of Bovine Skin from Tropically-Adapted Indicine and Temperate-Adapted Taurine Cattle Using RNA-Seq

Skin is the largest organ in mammals and the most exposed to the environment and is actively invaded by a host of hostile environmental insults precipitating physiological adjustments and molecular adaptive responses in animals. We hypothesized that there exist molecular and physiological differences between geographically separated cattle species that confer geographically specific adaptation potential to environmentally induced insults. Given the lack of data on the transcriptome profile of cattle skin, we investigated the skin transcriptomes of 2 tropically-adapted White Fulani (WF) and 2 temperate-adapted Angus (AG) cattle using RNA-Seq approach. Approximately 47 million reads were obtained per animal using the Illumina HiSeq 2000. Tryptophan 2,3-dioxygenase (TDO2), arachidonate 12-lipoxygenase epidermal-type (ALOX12E) were observed to be most significantly up-regulated in WF compared to AG while the most significantly down-regulated genes in WF compared to AG were synaptotagmin 4 (SYT4),  tyrosinase-related protein 1 (TYRP1), adinopectin C1Q and collagen domain (ADIPOQ). Gene ontology analysis using GOSeq identified extracellular region, melanin metabolic process, inflammatory response, response to wounding and response to external stimulus as the most enriched categories. Differential gene expression using KEGG pathway analysis revealed PPAR signaling, arachinodic acid, extracellular matrix receptor interaction, tyrosine metabolism and melanogenesis as the main pathways that are differentially regulated between the skins of WF and AG cattle. We anticipate this investigation to be a stepping stone for future studies to identify environmentally induced transcriptomic signatures specific to adaptive abilities of temperate- and tropically- adapted cattle.