PstI Restriction Fragment Length Polymorphism Research Articles

Activatable Shiga toxin 2d (Stx2d) in STEC strains isolated from cattle and sheep at slaughter

Shiga toxin producing Escherichia coli (STEC) harbouring the stx 2d-activatable gene and expressing the mucus- and elastase-activatable phenotype have been associated with severe outcomes of human disease. However, there is limited data available on the occurrence of such strains in livestock reservoirs. In this study, we analyzed 11 STEC strains isolated from healthy cattle and sheep at slaughter that were originally detected to contain the stx 2c allele, for the presence of the stx 2d-activatable genotype. Ten of the eleven strains displayed the stx 2d-activatable genotype as determine by PstI restriction fragment length polymorphism (RFLP) of 890-bp fragments of their stx genes. However, only in 6 of the 10 strains whose stx genes were sequenced, the presence of stx 2d-activatable could be confirmed based on the predicted amino acid sequence of their StxA subunits; the remaining four strains contained Stx2c A subunit. Five of the six strains which contained stx 2d-activatable displayed the activatable phenotype on Vero cells. Genes for adhesins such as the outer membrane protein intimin ( eae), which is essential for the intimate attachment and the formation of attaching-and-effacing lesions on intestinal epithelial cells, or the STEC autoagglutinating adhesin ( saa), potentially important in eae-negative STEC, were not detected. Moreover, all the strains tested negative for EHEC- hlyA encoding enterohaemorrhagic E. coli (EHEC) hemolysin. To our knowledge, this is the first study that reports the presence of STEC harbouring stx 2d-activatable and producing the activatable Stx2d in fecal samples of sheep. Therefore both cattle and sheep are reservoirs of such strains and potential sources of human infections. This is of particular importance, because in contrast to other eae-negative STEC, strains producing Stx2d activatable may cause severe diseases such as bloody diarrhoea and haemolytic uremic syndrome in humans.

Use of DNA polymorphisms of the apolipoprotein genes to study the role of genetic variation in the determination of serum lipid levels.

Cloned DNA probes for the apolipoprotein B (apoB) gene and the gene cluster for apoA-I/C-III/A-IV were used to detect restriction fragment length polymorphisms (RFLPs) at these two loci. Samples have been obtained from clinically well individuals, and the RFLP genotypes of each individual have been determined. The data show that at the locus for apoB, genetic variation associated with an RFLP detected by the enzyme XbaI (but not that associated with RFLPs detected by MspI or EcoRI) is involved in determining the normal levels of serum total cholesterol and low density lipoprotein (LDL) cholesterol. In our study, genetic variation associated with the XbaI RFLP accounts for 14% of the total phenotypic variance in cholesterol levels. Information from all three RFLPs can be used in conjunction to give a better definition of the underlying genetic variation. Data from a second study show that genetic variation in the apoA-I/C-III/A-IV gene cluster, associated with the PstI RFLP, is involved in determining the level of apoA-I and, to a lesser extent, the levels of high density lipoprotein (HDL). When genotypes from three RFLPs were used in conjunction as a haplotype, genetic variation in this gene cluster was shown to account for 16% of the phenotypic variance in apoA-I concentration and for 8% of the phenotypic variance in HDL concentration in our sample. These associations suggest that the isolation and sequencing of the apoB and the apoA-I/C-III/A-IV genes from different individuals will give useful information about how changes in the DNA sequence of these genes may lead to alterations in the levels of their respective apolipoproteins, in the level of the lipoproteins with which they are associated and, possibly, in the levels of lipids in the serum.

DRB3.2 gene polymorphism and its association with pashmina production in Changthangi goat

PstI and TaqI restriction fragment length polymorphism (RFLP) of caprine DRB3.2 revealed three genotypes under each RFLP in Changthangi goat. The genotypic and allelic frequency in PstI RFLP was calculated as 0.07, 0.72 and 0.20 for PP, Pp and pp genotypes and 0.43 and 0.57 for P and p alleles. In TaqI RFLP the frequencies were observed as 0.11, 0.61 and 0.27 for TT, Tt and tt genotypes and 0.41, 0.59 for T and t alleles. Alignment study indicates variability of nucleotides and amino acids between alleles and different breeds of goats. The nucleotide sequences reported in this paper have been submitted to the European Molecular Biology Laboratory GenBank and the accession numbers were AY496935, AY496061 and AY496062. A significant affect (P <or= 0.05) of MHC DRB3.2 PstI polymorphism was found on the first and second year of pashmina production.

Genetic polymorphism in cytochrome P450 2E1, salted food and colorectal cancer susceptibility: a case-control study

To investigate PstI allelic variants of cytochrome P450 2E1 (CYP2E1), the interaction effect on salted food and their role in risk for colorectal cancer. The genotypes of CYP2E1 PstI restriction fragment length polymorphism were analyzed in 126 colorectal cancer cases and 343 normal controls. The unconditional logistic regression was applied to estimate the OR and its 95% CI. The CYP2E1 C1/C1, C1/C2 and C2/C2 genotypes were found respectively in 61.8%, 35.8% and 2.4% of normal control, similar to rectal cancer cases. The percentage of PstI variant genotype (54.9%: 52.9% C1/C2 and 2.0% C2/C2) in colon cancer cases was significantly higher than that in controls (adjusted OR1.979, 95% CI 1.090 approximately 3.595). Stratified analysis suggested an interaction between CYP2E1 C2 allele and salted food. The odds ratio (OR) for the CYP2E1 variant genotype, salted food eaten weekly or biweekly and eaten every day or every other day were 1.935, 2.122 and 2.315, respectively, while those of salted food combined with variant genotype eaten weekly or biweekly and eaten every day or every other day were 2.272 and 3.127. The role in risk for rectal cancer was different from that for colon cancer. Whatever the CYP2E1 genotype is, the risk for rectal cancer came to marked when salted food was consumed weekly or biweekly (OR = 2.646 and 2.297, respectively). However, none but the combined effect of variant genotype and salted food eaten every day or every other day had the notably risk for colon cancer and the odds ratio suddenly increased to 4.262 (95% CI 1.395 approximately 13.017), 1.69-fold higher than that of wild genotype (P = 0.072). The CYP2E1 C2 allele is a susceptibility factor for colorectal cancer, especially for colon cancer, and there is an apparent gene-environment interaction between the susceptible genotype and salted food.

A standardised restriction fragment length polymorphism (RFLP) method for typing Mycobacterium avium isolates links IS 901 with virulence for birds

A standardised method for PvuII– PstI–IS 901 restriction fragment length polymorphism (RFLP) typing was developed and evaluated against 173 isolates of Mycobacterium avium subsp. avium and M. avium subsp. silvaticum originating from birds ( N=46) and their aviaries ( N=5), pigs ( N=85), cattle ( N=18), reference serotype strains ( N=9), humans ( N=7), a horse ( N=1), a nutria ( N=1), and strain M. avium subsp. avium ST 18 (formerly M. avium subsp. paratuberculosis ST 18). PvuII–IS 1245 RFLP typing was also performed on all isolates. DNA was digested in parallel by restriction endonucleases PvuII or PstI and hybridised to standard probes prepared by PCR. DNA fingerprints were scanned by CCD camera and analysed by the Gel Compar (Applied Maths, Version 4.1, Kortrijk, Belgium) software using a standard isolate control profile. A total of 52 PvuII– PstI RFLP profiles was described including 25 PvuII RFLP profiles designated A to Y and 25 PstI RFLP profiles designated A1–L3. Profiles were found to be stable in vivo and in vitro after multiple subcultures. High IS 901 copy number was associated with a “bird” PvuII–IS 1245 RFLP profile and low IS 901 copy number with M. avium subsp. avium isolates from humans and the nutria. A virulence assay of 100 IS 901-positive isolates using intramuscular infections of pullets showed 83 isolates differentiated into 32 RFLP types to be virulent and 17 isolates differentiated into 12 RFLP types as nonvirulent. Attenuation of virulence for pullets could be attributed to either multiple in vitro subculture, polyclonal infection or human passage and was not related to IS 901 or IS 1245 profiles.

Overweight, but not hypertension, is associated with SAH polymorphisms in Caucasians with essential hypertension.

The gene SAH (chromosome 16p12.3) is of interest in the etiology of human hypertension. In Caucasians a PstI restriction fragment length polymorphism (RFLP) of SAH has been correlated with body weight in individuals with hypertension. To extend this finding we carried out a case-control study of several recently identified polymorphisms in SAH: 1) an insertion/deletion of TTTAA at nucleotide --1037 in the promoter; 2) an insertion/deletion of two Alu like sequences in intron 1; and 3) an A-G variant in intron 12 located 7 bp upstream from exon 13. Subjects were 121 hypertensives with 2 hypertensive parents and 178 normotensives whose parents were both normotensive. All were Anglo-Celtic Caucasians and 51% of the hypertensives were overweight (body mass index (BMI)>25 kg/m2). The SAH promoter and intron 1 variants, but not the intron 12 or PstI RFLP, were in linkage disequilibrium (LD) (D'=100%, p<0.001). We found no association between any of the polymorphisms and hypertension. However, the frequency of the minor allele of the intron 1 polymorphism (0.20) was higher in overweight than in normal weight hypertensives (0.07) (p=0.013). This association was supported by the weak tracking of plasma lipid variables with this allele (p values=0.01-0.04), although these lost their statistical significance after correction for multiple comparisons. In conclusion, the present data offers support for variation in SAH having a role in predisposition to overweight in hypertensives.

Lack of evidence for a significant association between nonsyndromic cleft lip with or without cleft palate and the retinoic acid receptor alpha gene in the Japanese population.

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is one of the most common craniofacial malformations. Both genetic and environmental factors are thought to be involved in the pathogenesis. The retinoic acid receptor alpha ( RARA) is one of the candidate genes for the pathogenesis of NSCLP. An association between a PstI restriction fragment length polymorphism or D17S579 microsatellite marker polymorphism of the RARA gene and NSCLP was previously suggested, but no nucleotide change that may influence the gene expression or the protein sequence has been reported to date. To investigate the possible association between the RARA gene and NSCLP in Japanese patients, we performed a transmission disequilibrium test (TDT) using three microsatellite markers at the RARA locus in 48 parent-offspring trios. The allele-wise TDT did not show evidence of an association between the RARA gene and NSCLP. We also screened nucleotide changes in eight patients with family histories using exon-by-exon direct sequencing. We found a novel nucleotide change (1161C>T) that is located in exon 1 of the RARA gene in one patient whose father also had the disease. Because the 1161C>T was inherited from the patient's healthy mother, the mutation was not considered to be responsible for NSCLP. We then screened all probands for the nucleotide changes in the promoter region of the RARA gene using denaturing high-performance liquid chromatography. A novel nucleotide length polymorphism of a thymidine tract was identified in three patients. No association between this polymorphism and NSCLP was observed. Our findings suggest that the RARA gene variations do not contribute to the development of NSCLP in the Japanese population.

Trait association of a genetic marker near the IGF-I gene in egg-laying chickens.

The insulin-like growth factor I (IGF-I) gene was screened for genetic variants associated with trait means and trait correlations. Analysis of an unselected randomly mated White Leghorn population revealed a PstI restriction fragment length polymorphism (RFLP) in the 5' region of the gene which segregated at a frequency of 0.83 for the PstI(+) allele (presence of a PstI restriction site). A comparison of the three genotypic classes revealed that the PstI(-/-) genotype was associated with a significantly lower egg weight measured in three different time periods, while the PstI(+/-) genotype was significantly associated with a higher eggshell weight estimated from the egg weight and egg specific gravity. For eggshell weight, the effect was age dependent and significant only for the last two periods of egg laying. No genotype associations were found for body weight, feed consumption, and egg laying rates. Significant dominance effects of the IGF-I genotype were observed for two of the egg weight measurements and three of the eggshell weight estimates. Partial correlation analyses in the two most frequent genotypic classes, PstI(+/+) and PstI(+/-), revealed the presence of a regulatory loop between feed consumption, body weight, egg weight, and the rate of egg laying. Several aspects of this regulatory loop were different between the two genotypic classes. In particular, for the PstI(+/+) genotype, feed consumption was positively associated with egg weight, while there was no significant association for the PstI(+/-) genotype. Further, the degree of association of body weight with egg weight decreased with age in the genotypic class PstI(+/-), while it was constant for the PstI(+/+) genotype. The results indicated that the marker in the IGF-I gene was not only associated with changes in some trait means, but also with changes in the stability of the coordination between feed intake, body weight, and egg production traits.

??1A-Adrenergic receptor polymorphism

The alpha1-adrenergic receptor (alpha1-AR) mediates vasoconstriction and plays an important role in the regulation of vascular tone. Increased alpha1-AR-mediated vasoconstrictor sensitivity, increased vascular reactivity to stress, and an increased prevalence of hypertension occur in African-Americans. The human alpha1A-AR is the predominant alpha1-AR subtype in vascular smooth muscle. The potential relevance of alpha1A-AR genetic variation to ethnic differences in vascular response and to the pathogenesis of hypertension prompted us to determine the frequency distribution of a recently identified polymorphism (Arg492 to Cys) in the alpha1A-AR in normotensive and hypertensive black and white American individuals. Polymerase chain reaction-based PstI restriction fragment length polymorphisms in the human alpha1A-AR gene were determined in 231 African-American and 282 Caucasian individuals, both with and without hypertension. There were marked differences in the genotypic and allelic distributions of the Arg492 to Cys alpha1A-AR polymorphism between African-American and Caucasian individuals (Cys492/Cys492 genotype, normotensive: 7.6% versus 30.1%; hypertensive: 7.1% versus 26.2%; Cys492 allele, normotensive: 29.5% versus 53.8%; hypertensive: 28.8% versus 55.2%; blacks versus whites, P < 0.0001). The frequency of the variant Cys492 allele was similar in normotensive and hypertensive individuals, both in African-Americans (29.5% versus 28.8%) and Caucasians (53.8% versus 55.2%). There were no significant intergenotypic differences in blood pressure (all P > 0.05). The data indicate that this polymorphism is not associated with essential hypertension in black or white Americans, but that the frequency of the alpha1A-AR Arg492 allele occurs significantly more commonly in African-Americans than in Caucasians. The potential role of the Arg492 to Cys alpha1A-AR polymorphism in ethnic differences in vascular alpha1-adrenergic response requires further investigation.

Associations between cytochrome P4502E1 genotype, mutagen sensitivity, cigarette smoking and susceptibility to lung cancer.

Cytochrome P4502E1 (CYP2E1) is involved in the metabolic activation of carcinogenic N-nitrosoamines. We therefore assessed the genotype frequencies of PstI or RsaI CYP2E1 restriction fragment length polymorphisms and another susceptibility marker, mutagen sensitivity, in 137 lung cancer cases (92 African American and 45 Mexican American) and 206 controls (114 African American and 92 Mexican American) identified in a molecular epidemiological study of lung cancer. The CYP2E1 c1/c1 genotype was found in 86.7% of Mexican American cases, 70.6% of Mexican American controls, 89.1% of African American cases and 86.8% of African American controls. By multivariate analysis, this genotype was found to be associated with a 14.0-fold increased risk of lung cancer in Mexican Americans but not in African Americans; a 9.9-fold increased risk of lung cancer in Mexican American former smokers, but not in non-smokers or current smokers; a 15-fold increased risk of lung cancer in Mexican American males, but not in females. Patients with the susceptible genotype appeared to have developed cancer at an earlier age and with lower cigarette pack-year of exposure than did patients with the c1/c2 or c2/c2 genotypes. Stratified analysis suggested a greater than multiplicative interaction between cigarette smoking and CYP2E1 c1/c1 genotype, although not statistically significant. The odds ratios (ORs) for the CYP2E1 c1/c1 genotype, cigarette smoking and both risk factors combined were 1.3, 6.7 and 16.3, respectively. The association between CYP2E1 c1/c1 genotype and pack-years of smoking followed the same pattern. The interaction between mutagen sensitivity and CYP2E1 c1/c1 genotype was especially strong in former smokers (the ORs for the CYP2E1 c1/c1 genotype, mutagen sensitivity and both risk factors combined were 3.9, 5.4 and 23.0, respectively). Therefore, the data suggest that individuals who lack a c2 allele might be at higher risk for developing lung cancer.

Association analyses of S(A) gene variant in essential hypertensives.

A gene designated S(A) has been implicated in hypertension (HT) in rat genetic models and Japanese HT patients. However, a linkage study in whites was negative. Because of the limitations of genetic analyses, confirmation in different settings is imperative. Therefore, we conducted a cross-sectional case-control study involving 106 HT and 96 normotensive (NT) white subjects. A polymerase chain reaction technique was developed for PstI restriction fragment length polymorphism (RFLP) determination. We could find no association of this RFLP with HT (frequency of minor allele, A2 = 0.11 in HTs v 0.07 in NTs). However, A2 displayed an association with increase in body mass index in HTs: for a body mass index mean of 26 kg/m2 or more, A2 = 0.17 compared to 0.06 for body mass index of less than 26 kg/m2 (chi2 = 6.4, P = .01; odd ratio 3.4, 95% confidence interval 1.2 to 10.0); for a body mass index of 28 kg/m2 or more, A2 = 0.20 (chi2 = 10.4, P = .001; odds ratio 4.0, 95% confidence interval 1.5 to 10.5). Furthermore, A2 tracked significantly with elevation in body mass index in the HTs (F = 4.8, P = .01 by one-way ANOVA). In conclusion, we could find no association of S(A) genotype with HT, but obtained preliminary evidence for a possible association with variation in body mass index in a severely affected HT group with a strong family history of HT.

Human hepatocyte nuclear factor-4 (hHNF-4) gene maps to 20q12-q13.1 between PLCG1 and D20S17.

Human hepatocyte nuclear factor 4 (hHNF-4) is a member of the nuclear hormone receptor superfamily and an important transcription factor and developmental regulator of liver-specific genes. Distinct hHNF-4 cDNAs corresponding to various HNF-4 isoforms have been recently characterised. Three cDNAs, hHNF-4A, B and C, are considered splice variants of a single hHNF-4 gene. We have mapped hHNF-4 to 20q12-q13.1 between PLCG1 and D20S17 by genetic linkage analysis, taking advantage of an adjacent PstI restriction fragment length polymorphism, (RFLP), and by fluorescence in situ hybridisation. hHFN-4 maps to chromosome 20 in a region syntenic with mouse chromosome 2 where the hnf-4 homologue has been assigned.

IgE, TNFα, IL1 β, IL4 and IFNγ gene polymorphisms in sheep selected for resistance to fleece rot and flystrike

Investigation of restriction fragment length polymorphisms (RFLPs) associated with immunoglobulin E (IgE) and cytokine genes in the sheep genome revealed polymorphisms in the IgE constant heavy chain, interferon γ and interleukin 4 genes. No polymorphisms were found in interleukin 1β or tumour necrosis factor α. PstI and BamHI RFLPs in the IgE gene showed differences in frequency between animals selected for resistance or susceptibility to fleece rot and blowfly strike.

A PstI restriction fragment length polymorphism in the 5' untranslated region of DRD4 is not associated with schizophrenia.

We detected a PstI restriction fragment length polymorphism in the 5'-non-coding region of the dopamine D4 receptor gene (DRD4), making it the seventh known polymorphism for DRD4. DNA polymorphisms in the putative regulatory region of DRD4 are of interest because of the reported six-fold increase in D4 receptors in post-mortem schizophrenic brain tissue [Seeman P, Guan HC, Van Tol HHM (1993) Nature, 365, 441-445]. We found no difference in the PstI allele frequencies between DSM-III-R schizophrenia patients (0.76 and 0.24, n = 41), and matched control Caucasians (0.77 and 0.23, n = 46). The PstI DRD4 polymorphism has potential use in linkage and association studies with neuropsychiatric and cardiovascular disorders.

An investigation of whether polymorphisms of cytochrome P4502E1 are genetic markers of susceptibility to alcoholic end-stage organ damage in a Chinese population

The human cytochrome P4502E1 gene (P4502E1), coding for an ethanol-inducible nitrosamine-metabolizing P-450, is involved in the metabolism of ethanol and many known carcinogens. Recently, restriction fragment length polymorphisms (RFLPs) within the P4502E1 have been suggested as genetic markers of susceptibility to alcohol-induced liver disease but the previous studies disagree whether alcoholics with c1 or c2 allele are more susceptible to alcohol-induced liver disease. Using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, we determined the RsaI and PstI polymorphism of P4502E1 in 77 Chinese alcoholic patients (54 with alcohol-induced cirrhosis and 23 with acute alcohol-induced pancreatitis) and 164 non-alcoholics and compared them with previously published data. The PCR-RFLPs showed three P4502E1 genotypes: type A, homozygote cl/cl; type B, heterozygote cl/c2; and type C, homozygote c2/c2. The RsaI and PstI polymorphism of P4502E1 were completely linked in both Chinese alcoholics and nonalcoholic controls. The rare allele (c2) occurs at similar frequency of 0.232 and 0.234 ( P > .05) in nonalcoholic controls and alcoholics, respectively. The genotype distributions of P4502E1 between Chinese alcoholics and nonalcoholics are not significantly different. The genotype and allele frequencies of P4502E1 for Chinese are significantly different from those of Swedes, European-Americans, and African-Americans, respectively ( P < .00001), but very similar to Japanese ( P > .05). In conclusion, ethnic variations exist between Asians and Caucasians and between Asians and African-Americans. No allelic variants at loci associated with RsaI/ PstI RFLPs result in phenotypes displaying greater susceptibility to alcohol-induced cirrhosis or alcoholism in Chinese populations, which contradicts previous reports from Japanese groups.

Nested PCR allows the characterization of TaqI and PstI RFLPs in the second exon of the caprine MHC class II DRB gene

A nested polymerase chain reaction (PCR) method has been developed to obtain a specific amplification of the second exon of the caprine MHC class II DRB gene. The specificity of this method has been verified by cloning and sequencing the PCR product and comparing its sequence to 21 previously published caprine DRB second exon allelic variants. Nucleotide identity between this sequence (Caae-DRB23) and other caprine DRB alleles ranged between 85.6% (Caae-DRB22) and 96.5% (Caae-DRB5). Caae-DRB5 and Caae-DRB23 sequences diverged in five amino acid substitutions (70, 71, 73, 74, 78), all of them placed at the antigen binding site. Likewise, the restriction polymorphism of the caprine DRB second exon has been analyzed and two different restriction patterns have been found depending on the presence or absence of a TaqI site and a PstI site at positions 122 bp and 241 bp of the PCR product respectively. TaqI and PstI RFLPs were also analyzed in other artiodactyla species. While PstI RFLP was found not only in goats but also in cattle, sheep and pigs, TaqI RFLP was only detected in goats. In all of these species close associations were detected between the presence of TaqI and PstI restriction sites and amino acid substitutions at positions 40 and 78 respectively, suggesting that PCR restriction fragment length polymorphism (RFLP) could be a useful tool in relating amino acid substitutions at critical positions with disease resistance.

Genetic analysis of three loci homologous to human G9a: evidence for linkage of a class III gene with the chicken MHC

The cDNA clones of two newly discovered genes in the class III region of the human major histocompatibility complex (MHC) were hybridized to chicken DNA. One of these cDNA clones (pG9a-4C7), which detects the single-copy human G9a (BAT8) gene, gave a repeatable restriction pattern. This heterologous cDNA clone was used to detect and map three different PstI restriction fragment length polymorphisms among the two internationally recognized chicken reference populations. Two of the loci were unlinked to previously mapped markers, but one polymorphism cosegregated with the EaB locus in the Compton mapping population. These results provide evidence that some genes of the mammalian class III region, such as G9a, may be linked to the MHC in chickens.

Detection of genomic heterogeneity in Streptococcus suis isolates by DNA restriction fragment length polymorphisms of rRNA genes (ribotyping).

Whole-cell chromosomal digests of 54 isolates of Streptococcus suis encompassing all known serotypes from a geographically varied collection were examined by PstI restriction fragment length polymorphisms and then hybridized with a digoxigenin-11-dUTP-labeled cDNA probe transcribed from a mixture of 16S and 23S rRNAs from Escherichia coli MRE600. The hybridization patterns showed genetic heterogeneity within and between S. suis serotypes. Most isolates (87%) representing 28 serotypes contained a common band at approximately 1.8 kb. However, 13% of the isolates representing seven serotypes lacked the 1.8-kb band, indicating that the species as currently defined is diverse. Nonetheless, the 1.8-kb band may be a useful genotypic marker for identification of most S. suis isolates. We tested the ability of this technique to discriminate between virulent and avirulent S. suis type 2 isolates. A virulent strain of S. suis type 2 could be distinguished from avirulent strains by the presence of specific bands. No correlation was obvious between band pattern and hemolysin production.

Analysis of cytochrome P450 2E1 genetic polymorphisms in relation to human lung cancer: Kato S, Shields PG, Caporaso NE, Sugimura H, Trivers GE, Tucker MA et al. Laboratory of Human Carcinogenesis, Division of Etiology, National Cancer Institute, Bethesda, MD 20892. Cancer Epidemiol Biomarkers Prev 1994;3:515–518

Human cancer risk assessment using molecular genetic techniques is a rapidly emerging field. Many studies suggest that both inherited and acquired genetic predispositions play an important role in carcinogenesis. Cytochrome P450 (CYP) 2E1 is involved in the metabolic activation of N-nitrosamines and other low molecular weight compounds. A recently described genetic polymorphism of CYP2E1 [DraI restriction fragment length polymorphism (RFLP)] has been associated with an increased risk of lung cancer in Japanese. We have assessed the allelic frequency of three RFLPs (PstI, RsaI, and DraI) in African-Americans (n = 109), Caucasian Americans (n = 153), and octogenarian Japanese (n = 42), and also in a United States case-control study of lung cancer (histologically confirmed lung cancer, n = 58; controls, n = 56; total, n = 114). The relationship of the CYP2E1 DraI polymorphism to other CYP2E1 polymorphisms (PstI and RsaI RFLP) was examined. The allelic frequency of the DraI C minor allele for all subjects was 0.09 in Caucasians, 0.09 in African-Americans, and 0.31 in Japanese. In the case-control study of lung cancer, no association of the CYP2E1 DraI genotype with lung cancer was found (odds ratio, 1.57; 95% confidence interval, 0.59-4.18). Comparison after discordant CYP2E1 genotypes suggests the presence of different haplotypes in Americans and Japanese. These results indicate that the CYP2E1 DraI RFLP is probably not a cancer risk factor in United States Caucasian or African-Americans, although statistical power is limited given the low frequency of the CYP2E1 DraI C minor alleles.

A PstI restriction fragment length polymorphism in sheep detected with a human myelin basic protein (MBP) probe.

A PstI restriction fragment length polymorphism in sheep detected with a human myelin basic protein (MBP) probe.