Cloning, characterization, and expression features of chicken CDS2 splicing variants

Abstract

Background: The CDS gene encodes the CDP-diacylglycerol synthase enzyme that catalyzes the formation of CDP-diacylglycerol (CDP-DAG) from phosphatidic acid. At present, there are no reports of CDS2 in birds. Here, we identified chicken CDS2 transcripts, explored the spatio-temporal expression profiles of total CDS2 and the longest transcript variant CDS2-4, and investigated the effect of exogenous insulin on total the mRNA level of CDS2.Results: Four transcripts of chicken CDS2 (CDS2-1, -2, -3, and -4) were identified, which were alternatively spliced at the 3′-untranslated region (UTR). Chicken CDS2 was located at chr.22, where there was a chromosomal fusion/break event in the evolution of mammals and birds. CDS2 was widely expressed in all tissues examined and the longest variant CDS2-4 was the major transcript. Both total CDS2 and CDS2-4 were prominently expressed in adipose tissue and the heart, and exhibited low expression in the liver and pectoralis of 49 day-old chickens. Quantitative real-time PCR revealed that total CDS2 and CDS2-4 had different spatio-temporal expression patterns in chicken. Total CDS2 exhibited a similar temporal expression tendancy with a high level in the later period of incubation (embryonic day 19 [E19] or 1-day-old) in the brain, liver, and pectoralis. While CDS2-4 presented a distinct temporal expression pattern in these tissues, CDS2-4 levels peaked at 21 days in the brain and pectoralis, while liver CDS2-4 mRNA levels were highest at the early stage of hatching (E10). Total CDS2 (P < 0.001) and CDS2-4 (P = 0.0090) mRNA levels in the liver were differentially regulated throughout development of the chicken. Exogenous insulin significantly downregulated the level of total CDS2 at 240 min in the pectoralis of Silky chickens (P < 0.01). Total CDS2 levels in the liver of Silky chickens were higher than that of the broiler in the basal state and after insulin stimulation.Conclusion: Chicken CDS2 has multiple transcripts with variation at the 3′-UTR, which was prominently expressed in adipose tissue. Total CDS2 and CDS2-4 presented distinct spatio-temporal expression patterns, and they were differentially regulated with age in liver. Insulin could regulate chicken CDS2 levels in a breed- and tissue-specific manner.