ABSTRACT
Objective This study was aimed to characterize the swine leukocyte antigen( SLA) class I genes of GGTA1 -/ - Wuzhishan minipigs and compare their similarity to human leukocyte antigen( HLA) . It has important implica?tions for understanding the cellular rejection in xenotransplantation. Methods Specimens of ear tissue from six founding GGTA1 -/ - Wuzhishan minipigs were collected, and the SLA class I genes (SLA?1, SLA?3, SLA?2) were amplified by RT?PCR. Purified products were cloned into pEASY?T1 vectors and sequenced, followed by BLAST alignment and using bioin? formatc analysis to characterize the SLA class I genes and compare with the similarity to HLA. Results A total of six al?leles were detected, among them alleles were previously reported (SLA?1?0703,SLA?2?1102, SLA?3?0401, SLA?3?0403), and the other were novel (SLA?1?0401wz01, SLA?2?11wz01). The homology between alleles of SLA class I genes in Wuzhishan minipigs and HLA was from 70?5% to 72?1%. The homology analysis of critical amino acid residues on HLA binding with human CD8 + molecules showed that SLA?1?0401wz01, SLA?1?0703, SLA?2?11wz01, SLA?2?1102 and SLA?3?0401 occurred mutant at amino acid positions 225 and 228 ( T→S,T→M) , whereas the other loci were highly conserved. There was a high homology at amino acid level between SLA?2?11wz01, SLA?2?1102 and HLA class I genes which are NK cell KIRs binding sites. Conclusions The amino acid sequences of SLA class I genes of GGTA1 -/ -Wuzhishan minipigs have a high homology to HLA. From the point of view of cell?mediated xenograft rejection, the amino acid sequences of SLA class I genes of GGTA1 -/ - Wuzhishan minipigs have a high homology to HLA, therefore, Wzhishan minipigs may become a good potential donor for pig?human xenotransplantation.
ABSTRACT
Somatic cell nuclear transfer (SCNT) is a technology by which a highly differentiated somatic nucleus is transferred into an enucleated oocyte to generate a reconstructed embryo that subsequently develops to an offspring. However, to date, the efficiency of cloned animal is still low. The major reason is incomplete nuclear reprogramming of donor cells after nuclear transfer, which results in abnormal epigenetic modifications, including DNA methylation, histone acetylation, gene imprinting, X-chromosome inactivation, and telomere length. Most improvements have been made in somatic epigenetic reprogramming with small molecules and manipulating expression of specific genes. It is expected that SCNT will soon have broad applications in both basic research and practical production. In this review, we summarize the recent progress in epigenetic reprogramming by somatic cell nuclear transfer; in particular, we focus on strategies for rescuing the epigenetic errors occurring during SCNT.
