RESUMO
BACKGROUND: Cytochrome P450 (CYP) 2C9 is an important enzyme involved in xenobiotics metabolism. This study investigated the association of CYP2C9 gene coding region polymorphisms with colorectal cancer (CRC) in Chinese Han population. METHODS: Four hundred and eighty-three healthy controls and 286 sporadic CRC patients participated in this study. Direct sequencing was used to identify the sequence polymorphisms. RESULTS: We detected the significant association of 2 coding region SNPs, rs1057910 and rs1057911, of CYP2C9 with the risk of developing sporadic CRC for Han Chinese. These 2 SNPs showed a strong linkage disequilibrium (LD) (r(2)=0.97, D'=0.985). Significantly different minor allele frequencies were found for SNPs rs1057910 and rs1057911 between the cases (7% and 7.2%, respectively) and controls (3% and 2.9%, respectively) with adjusted P=0.0004 and 0.0002, respectively. Individuals heterozygous for rs1057910A/C or rs1057911A/T showed 2.589-fold (95% CI: 1.549-4.330) or 2.770-fold (95% CI 1.653-4.643) increased risk of developing sporadic CRC. We did not detect any homozygote minor allele carrier for either rs1057910 or rs1057911 in our study population. The CRC association appeared to be more evident for individuals over age 50 y, for men, and for rectum cancer site. CONCLUSION: There is an association of CYP2C9 coding region polymorphisms with the risk of developing CRC in Han Chinese after genotyping cases and controls recruited from different locations in China.
Assuntos
Hidrocarboneto de Aril Hidroxilases/genética , Neoplasias Colorretais/genética , Polimorfismo Genético/genética , Alelos , Estudos de Casos e Controles , China/epidemiologia , Neoplasias Colorretais/epidemiologia , Citocromo P-450 CYP2C9 , Feminino , Predisposição Genética para Doença , Genótipo , Inquéritos Epidemiológicos , Homozigoto , Humanos , Masculino , Prontuários Médicos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Fumar/efeitos adversosRESUMO
RP2 is an X-linked retinitis pigmentosa gene, which was newly discovered by positional cloning. A polymerase chain reaction (PCR) was conducted to screen a full-length cDNA fragment, defined as hRP2a, which included the coding region of hRP2, in a human retina cDNA library. HRP2a gene was cloned into the pJLA503 vector and hRP2 gene was subcloned into the expression vector pP(RO)EX HTa. Polymorphism was demonstrated at two sites through DNA sequencing. The recombinant pP(RO)RP2 was transformed into Escherichia coli strain DH5alpha and the expression of a 6xHis tagged hRP2 fusion protein was induced by IPTG. Band density scanning of stained gel was performed to estimate the percentage of the recombinant protein in the total bacterial protein. The ratio was 7% when the expression was induced at 30 degrees and was 5.6 % at 37 degrees. The cloning and expression of hRP2 gene in E.coli established a basis for the further purification and studies of RP2 for its physiochemical identity, immunohistochemistry and structure-function relationship.
RESUMO
The Xp11.2 region o the human X chromosome contains genes involved in a number of inherited diseased, with at least one locus that escapes X chromosome inactivation, as well as abnormal methylation polymorphism. We isolated a series of yeast artificial chromosome (YAC) clones by hybridization screening with DNA probes localized within this region and assembled them into a 4.3 Mb contig spanning from Xp11.21 to Xp11.23 by a combination of Alu-PCR fingerprinting, STS-PCR and DNA probe cross hybridization. On the basis of these overlapping YAC clones we have constructed the long-range restriction map of this interval and placed exactly some DNA markers. Four CpG-dense regions between ARAF1 and OATL2 were identified based on the long-range restriction mapping, which indicated the distribution of genes within this interval. It should assist in the future nucleic acid sequence analysis and novel gene identification in this region.
RESUMO
One hundred and fifty-one YACs were selected from three libraries with a series of STS and other DNA probes of the human X chromosome p11.2 - p21.3 region. The YAC contigs, spanning about 35cM in all and generally cover the whole region, were constructed based on the physical analysis of the positive clones. A total of seventy-seven DNA markers of this region were located and ordered on this map with an average 454 kb spacing, in which fifty-three were polymorphic markers with an average 0.6 cM genetic spacing. These results facilitate the search for novel genes and the sequence analysis of this region.