It reveals that the MHC （major histocompatibility complex） gene product always involved in the control of immune response and disease resistance. Nowadays many studies have indicated the OLA （ovine lymphocyte anti...It reveals that the MHC （major histocompatibility complex） gene product always involved in the control of immune response and disease resistance. Nowadays many studies have indicated the OLA （ovine lymphocyte antigen） DRB1 gene is associated with some sheep diseases. Tibetan sheep is one of the three major shag sheep breeds in China, and also have the largest number of China＇s sheep breeds. But till now no report has been seen on studying DRB1 gene in Tibetan sheep of China. To understand the evolution and provide the basis for sheep disease resistance, polymorphism in the exon2 ofDRB1 gene in Tibetan sheep was analyzed. The PCR-SSCP, cloning and sequencing were used to analyse DRB1 gene variation in 600 Tibetan sheep of China. And the genetic relationship and evolutionary significance of the alleles had also been analyzed. Total of 31 alleles were identified, in which 15 alleles had not been reported before. And there were 70 SNPs （single nucleotide polymorphisms） sites in 31 sheep DRB1 gene haplotypes, the proportion was 29.5% to the whole exort2 sequence. All of this indicated that DRB1 exon2 is highly polymorphic in Tibetan sheep. The variation identified here might have an impact on both the function and level of expression of the OLA-DRB1.展开更多
The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography. Selenium atoms in the nucleotides can serve as fine scatter...The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography. Selenium atoms in the nucleotides can serve as fine scattering centers in crystal diffraction. Towards the synthesis of multiple selenium atom-containing nucleotides, which offers strong phasing power to facilitate crys- tal structure determination, we report here the synthesis of the thymidine analogue containing two Se atoms in one nucleobase. The novel Se-containing nucleoside and oligonucleotide DNAs were synthesized and found with the red-shifted UV spectrum and yellow color. Their unique properties are useful in phase determination, nucleic acid-based detection as well as spectro- scopic studies of nucleic acids and nucleic acid-protein complexes.展开更多
文摘It reveals that the MHC （major histocompatibility complex） gene product always involved in the control of immune response and disease resistance. Nowadays many studies have indicated the OLA （ovine lymphocyte antigen） DRB1 gene is associated with some sheep diseases. Tibetan sheep is one of the three major shag sheep breeds in China, and also have the largest number of China＇s sheep breeds. But till now no report has been seen on studying DRB1 gene in Tibetan sheep of China. To understand the evolution and provide the basis for sheep disease resistance, polymorphism in the exon2 ofDRB1 gene in Tibetan sheep was analyzed. The PCR-SSCP, cloning and sequencing were used to analyse DRB1 gene variation in 600 Tibetan sheep of China. And the genetic relationship and evolutionary significance of the alleles had also been analyzed. Total of 31 alleles were identified, in which 15 alleles had not been reported before. And there were 70 SNPs （single nucleotide polymorphisms） sites in 31 sheep DRB1 gene haplotypes, the proportion was 29.5% to the whole exort2 sequence. All of this indicated that DRB1 exon2 is highly polymorphic in Tibetan sheep. The variation identified here might have an impact on both the function and level of expression of the OLA-DRB1.
文摘The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography. Selenium atoms in the nucleotides can serve as fine scattering centers in crystal diffraction. Towards the synthesis of multiple selenium atom-containing nucleotides, which offers strong phasing power to facilitate crys- tal structure determination, we report here the synthesis of the thymidine analogue containing two Se atoms in one nucleobase. The novel Se-containing nucleoside and oligonucleotide DNAs were synthesized and found with the red-shifted UV spectrum and yellow color. Their unique properties are useful in phase determination, nucleic acid-based detection as well as spectro- scopic studies of nucleic acids and nucleic acid-protein complexes.
