Isolation, sequence analysis and expression profile of a novel porcine gene, NIP7, differentially expressed in the Longissimus dorsi muscle tissues from Meishan, Meishan x Large White cross and Large White pigs.

In order to detect the molecular mechanism of heterosis in pigs, the mRNA differential display technique was performed to investigate the differences in gene expression in the Longissimus dorsi muscle tissues from Meishan, Meishan x Large White cross and Large White pigs. One novel gene that was differentially expressed was identified using semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and its complete cDNA sequence was obtained using the rapid amplification of cDNA ends (RACE) method. The nucleotide sequence of the gene is not homologous to any of the known porcine genes. The sequence prediction analysis revealed that the open reading frame of this gene encodes a protein of 180 amino acids that contains the conserved putative RNA-binding domain in PseudoUridine synthase and Archaeosine transglycosylase (PUA) and has high homology with the 60S ribosome subunit biogenesis protein NIP7 homolog of three species--human (98%), mouse (97%) and rat (96%)--so that it can be defined as swine 60S ribosome subunit biogenesis protein NIP7 homolog (NIP7). The tissue expression analysis indicated that the swine NIP7 gene is over expressed in muscle, heart, liver, fat, kidney, and lung, but weakly expressed in small intestine, ovary, and spleen. The genomic DNA sequence of swine NIP7 gene was finally amplified and result revealed that the swine NIP7 gene contains five exons and four introns. Our experiment is the first to establish the primary foundation for further research on the swine NIP7 gene.