Expression and imprinting analysis of the NESP55 gene in pigs

Most imprinted genes play important roles in a mammalian development. One of them is GNAS complex locus which codes for several imprinted or biallelically expressed transcripts. The function of some of them are well understood (for example GSα-guanine nucleotide binding, α -stimulating protein is essential element of cell signaling), whereas the others are little known. The function of NESP55 (Neuroendocrine secretory protein 55) remains elusive, although there are suggestions about its role in brain development. Imprinted genes are currently being studied as potential candidate genes for quantitative trait loci (QTLs) in farm animals. In our study, we analyzed tissue distribution of NESP55 mRNA in pigs and established imprinting status of this gene in the brain stem, muscle, kidney and liver at several developmental stages. NESP55 mRNA was most abundant in central nervous system (CNS) and pituitary. Substantial expression was also noticed in the kidney, testis and muscle. Moreover, we identified a 12-nucleotides deletion within the coding region of NESP55 (accession number ss#342570450) which was used in imprinting analysis. The deletion was very rare in the analyzed populations and present only in heterozygous form. The imprinting analysis showed that NESP55 is maternally expressed in young and adult pigs, similar to what was obtained in humans, mice and cattle.