The Bioinformatical Prediction Molecular Clone And Primary Identification Of Porcine Imprinted Genes

For most of the genes, both paternal and maternal alleles are expressed or repressed in relevant cells throughout development and in adults. However imprinted genes are quite different from that, only the paternal or maternal allele is expressed while the other is repressed by parent-of-origin-dependent epigenetic modification.The distinct character of imprinted genes is that all imprinted genes show either maternal-specific or paternal-specific mono-allelic expression. Most of the imprinted genes are found in clusters in the genome with at least one long non-coding RNA and several differentially methylated region (DMR) which can regulate the cluster. Imprinted genes also show temporal and spatial imprinting pattern, it may only imprinted in some tissues and some development periods. At the same time imprinted genes are conserved among viviparous mammals, especially eutherians, and, to a lesser extent, in marsupials.Imprinted genes play significant roles in the regulation of fetal growth, development, function of the placenta and postnatal behavior in mammals, correct regulation of imprinted genes is essential for normal mammalian development, many researches have reported that disruption of genomic imprinting is responsible for congenital disorders, cancers, and other types of diseases such as BWS (Beckwith-Wiedemann syndrome) and PWS (Prader-Willi syndrome). In the production of somatic cell nuclear transfer animal, abnormal expression of imprinted genes and abnormal methylation patterns in differentially methylated region (DMR) result in the high rate of abortion and abnormal development.Most genes known to be imprinted have been identified and studied in the human and the mouse. At present, there have144and more than70imprinted genes been identified in mouse and human, some of them are researched deeply at their function and DMR. However, there are only a small number of reported imprinted genes in pigs, only10or more genes are reported, only Igf2/H19DMRs are known. To increase our understanding of porcine imprinted genes, it is important to make a bioinformatical prediction of porcine imprinted genes, then molecular clone and identify the candidate genes.According to the conversion of imprinted genes in mammalian, we get the candidate porcine imprinted genes by blasting mouse imprinted genes sequences to porcine genome database by blast stand-alone on linux system. Then we clone four candidate genes related to embryo development by RT-PCR. At last we try to identify the imprinted pattern of Asb4by cSNP analysis of Large White, Landrace and their F1.The main results are as follows: (1) We acquire59candidate imprinted genes by blasting mouse imprinted genes sequences to porcine Refseq and Unigene database by blast stand-alone on linux system. Our results are reliable by finding known porcine imprinted genes in it.(2) We clone four candidate genes Asb4, Snrpn, Cd81and Grb10by RT-PCR, get their full length sequence.(3) We find a Aâ†'G cSNP between Large White and Landrace at77nucleotide in exon5and detect it in F1DNA and cDNA, it is heterozygous in era and umbilical cord in newborn piglet, and also is heterozygous in16tissues in one-month-piglet. This demonstrates that Asb4is not an imprinted gene in porcine.