Genomic structure, chromosomal localization and expression profile of a porcine long non-coding RNA isolated from long SAGE libraries.

Long non-coding RNA (long ncRNA) is a novel class of ncRNA that may be involved in critical cellular processes. A considerable number of mammalian long ncRNAs have now been isolated but only a small number of these nucleic acids have been functionally well characterized. In this study, to determine the structure, regulation and function of long ncRNA in pigs, TncRNA was isolated from this mammal and its potential function during pig foetus development was identified. We anticipated that this would provide new insights into functional genomic studies in the pig. Using LongSAGE libraries generated from Chinese indigenous Tongcheng and Landrace pigs at three prenatal stages, a novel porcine long ncRNA was identified, TncRNA, which was found to be differentially expressed during myogenesis. The full-length cDNA for this gene is 3409 bp, and it harbours a typical polyadenylation signal sequence located 18 bp upstream from the 3' poly (A) tail. Genomic sequence analysis showed that pig TncRNA is alternatively spliced and several transcripts were detected. Using the INRA-University of Minnesota porcine radiation hybrid panel, TncRNA was assigned to SSC2 and found to be closely linked to the microsatellite marker SW256. Porcine TncRNA was found to be expressed in all tissues examined but in variable amounts. Comparisons between the expression profiles of TncRNA at different development stages in Tongcheng and Landrace pigs revealed up-regulation of this molecule in prenatal skeletal muscle, and differential expression in 90-day-old foetal skeletal muscle between these two pig breeds. This is the first report to describe a long ncRNA in pig. Moreover, the distinct expression pattern and structure of porcine TncRNA suggest that it performs complex and critical functions during foetal development.