Molecular cloning and expression of the IL-10 gene from guinea pigs

The Guinea pig (Cavia porcellus) is one of the most relevant small animals for modeling human tuberculosis (TB) in terms of susceptibility to low dose aerosol infection, the organization of granulomas, extrapulmonary dissemination and vaccine-induced protection. It is also considered to be a gold standard for a number of other infectious and non-infectious diseases; however, this animal model has a major disadvantage due to the lack of readily available immunological reagents. In the present study, we successfully cloned a cDNA for the critical Th2 cytokine, interleukin-10 (IL-10), from inbred Strain 2 guinea pigs using the DNA sequence information provided by the genome project. The complete open reading frame (ORF) consists of 537 base pairs which encodes a protein of 179 amino acids. This cDNA sequence exhibited 87% homology with human IL-10. Surprisingly, it showed only 84% homology with the previously published IL-10 sequence from the C4-deficient (C4D) guinea pig, leading us to clone IL-10 cDNA from the Hartley strain of guinea pig. The IL-10 gene from the Hartley strain showed 100% homology with the IL-10 sequence of Strain 2 guinea pigs. In order to validate the only published IL-10 sequence existing in Genbank reported from C4D guinea pigs, genomic DNA was isolated from tissues of C4D guinea pigs. Amplification with various sets of primers showed that the IL-10 sequence reported from C4D guinea pigs contained numerous errors. Hence the IL-10 sequence that is being reported by us replaces the earlier sequence making our IL-10 sequence to be the first one accurate from guinea pig. Recombinant guinea pig IL-10 proteins were subsequently expressed in both prokaryotic and eukaryotic cells, purified and were confirmed by N-terminal sequencing. Polyclonal anti-IL-10 antibodies were generated in rabbits using the recombinant IL-10 protein expressed in this study. Taken together, our results indicate that the DNA sequence information provided by the genome project is useful to directly clone much needed cDNAs necessary to study TB in the guinea pig. The newly cloned guinea pig IL-10 cDNA and recombinant proteins will serve as valuable resources for immunological studies in the guinea pig model of TB and other diseases.     

Identification of bovine NPC1 gene cSNPs and their effects on body size traits of Qinchuan cattle

NPC1 gene is an important gene closely related to the Niemann–Pick type C (NPC). Mutations in the NPC1 gene tend to cause Niemann–Pick type C, a lysosomal storage disorder. Previous studies have shown that NPC1 protein plays an important role in subcellular lipid transport, homeostasis, platelet function and formation, which are basic metabolic activities in the process of development. In this study, to explore the association between the NPC1 gene variation and body size traits in Qinchuan cattle, we detected four novel coding single nucleotide polymorphisms (cSNPs) in the bovine NPC1 gene, including one missense mutation (SNP1) and three synonymous mutations (SNP2, SNP3 and SNP4). Population genetic analyses of 518 individuals and association correlations between cSNPs and bovine body size traits were conducted in this research. A missense mutation at SNP1 locus was found to be significantly related to the heart girth, hip width and body weight (P < 0.01 or P < 0.05, 3.5-year-old). Two synonymous mutations at SNP2 and SNP3 loci also showed significant effects on hip width (P < 0.05, 3.5-year-old). One synonymous mutation at SNP4 locus showed significant effect on body weight (P < 0.05, 2.0-year-old). Combined haplotypes H₂H₆ and H₆H₆ showed significant effects on body size traits such as heart girth, hip width, and body weight (3.5-year-old, P < 0.01 or P < 0.05). This study provides evidence that the NPC1 gene might be involved in the regulation of bovine growth and body development, and may be considered as a candidate gene for marker assisted selection (MAS) in beef cattle breeding industry.     

Analysis of genotype polymorphism of tumor-related genes harbored in chromosome arm lp and 8p in hepatocellular carcinoma patients by cSNP chip

The majority of single nucleotide polymorphisms (SNPs) found in the coding region (cSNPs) are single base substitutions that may or may not lead to amino acid substitutions,most of which are related to diseases.Some cSNPs may prove useful for their potential links to functional cSNPs via linkage disequilibrium mapping.We have selected 48 cSNPs located in the coding regions of 25 genes to construct the cSNP chip.These genes are harbored in the high frequency loss regions of the chromosome 1p and 8p and related with apoptosis,cell cycles,signal transduction,oncogene,tumor suppressor genes and so on.All of the cSNPs can lead to amino acid substitutions except TP73 (rs1801174).The PCR products amplified from 31 hepatocellular carcinoma (HCC) specimens were labeled with Dig-dUTP and then hybridized with the cSNP chips.The results showed that there was no hybridization signal when there was more than one site of mutation in the amplification sequence,indicating that the cSNP chip had a high sensitivity.The statistic data of the SNP (MT,homozygous and HT,heterozygous) in the HCC patients with different phenotypes (HBV +/-,differentiation stage,family history positive or negative,tumor size) indicated that the number of MT was distinctly different between patients with positive HBV and negative HBV.The MT and HT numbers of all the 48 cSNPs were significantly different between low differentiation and high differentiation HCC patients.The numbers of MT and HT were not different between positived and negative family history groups and between tumor size＞3 cm and≤3 cm groups.The study results provided useful information for understanding the molecular mechanisms of HCC development.     

Analysis of genotype polymorphism of tumor-related genes harbored in chromosome arm 1p and 8p in hepatocellular carcinoma patients by cSNP chip

The majority of single nucleotide polymorphisms (SNPs) found in the coding region (cSNPs) are single base substitutions that may or may not lead to amino acid substitutions, most of which are related to diseases. Some cSNPs may prove useful for their potential links to functional cSNPs via linkage disequilibrium mapping. We have selected 48 cSNPs located in the coding regions of 25 genes to construct the cSNP chip. These genes are harbored in the high frequency loss regions of the chromosome 1p and 8p and related with apoptosis, cell cycles, signal transduction, oncogene, tumor suppressor genes and so on. All of the cSNPs can lead to amino acid substitutions except TP73 (rs1801174). The PCR products amplified from 31 hepatocellular carcinoma (HCC) specimens were labeled with Dig-dUTP and then hybridized with the cSNP chips. The results showed that there was no hybridization signal when there was more than one site of mutation in the amplification sequence, indicating that the cSNP chip had a high sensitivity. The statistic data of the SNP (MT, homozygous and HT, heterozygous) in the HCC patients with different phenotypes (HBV+/−, differentiation stage, family history positive or negative, tumor size) indicated that the number of MT was distinctly different between patients with positive HBV and negative HBV. The MT and HT numbers of all the 48 cSNPs were significantly different between low differentiation and high differentiation HCC patients. The numbers of MT and HT were not different between positived and negative family history groups and between tumor size >3 cm and ⩽ 3 cm groups. The study results provided useful information for understanding the molecular mechanisms of HCC development.