Shigenori Murata

Multiple primer extension by DNA polymerase on a novel plastic DNA array coated with a biocompatible polymer

DNA microarrays are routinely used to monitor gene expression profiling and single nucleotide polymorphisms (SNPs). However, for practically useful high performance, the detection sensitivity is still not adequate, leaving low expression genes undetected. To resolve this issue, we have developed a new plastic S-BIO® PrimeSurface® with a biocompatible polymer; its surface chemistry offers an extraordinarily stable thermal property for a lack of pre-activated glass slide surface. The oligonucleotides immobilized on this substrate are robust in boiling water and show no significant loss of hybridization activity during dissociation treatment. This allowed us to hybridize the templates, extend the 3′ end of the immobilized DNA primers on the S-Bio® by DNA polymerase using deoxynucleotidyl triphosphates (dNTP) as extender units, release the templates by denaturalization and use the same templates for a second round of reactions similar to that of the PCR method. By repeating this cycle, the picomolar concentration range of the template oligonucleotide can be detected as stable signals via the incorporation of labeled dUTP into primers. This method of Multiple Primer EXtension (MPEX) could be further extended as an alternative route for producing DNA microarrays for SNP analyses via simple template preparation such as reverse transcript cDNA or restriction enzyme treatment of genome DNA.

Combination Analysis in Genetic Polymorphisms of Drug-Metabolizing Enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese Population

The Cytochrome P450 is the major enzyme involved in drug metabolism. CYP enzymes are responsible for the metabolism of most clinically used drugs. Individual variability in CYP activity is one important factor that contributes to drug therapy failure. We have developed a new straightforward TaqMan PCR genotyping assay to investigate the prevalence of the most common allelic variants of polymorphic CYP enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A5 in the Japanese population. Moreover, we focused on the combination of each genotype for clinical treatment. The genotype analysis identified a total of 139 out of 483 genotype combinations of five genes in the 1,003 Japanese subjects. According to our results, most of subjects seemed to require dose modification during clinical treatment. In the near future, modifications should be considered based on the individual patient genotype of each treatment.

The ACTN3 Gene is a Potential Biomarker for the Risk of Non-Contact Sports Injury in Female Athletes

Sports injuries can become serious impairments for all athletes. Most notably, female athletes are at higher risk than men for sports injury, for example, anterior cruciate ligament (ACL) disorder. However, there is currently no genetic marker to determine if a female athlete harbors a predisposition for muscle trauma. Hence, we performed single nucleotide polymorphism genotyping of the α-actinin-3 (ACTN3), angiotensin-converting enzyme (ACE), and uncoupling proteins (UCP1, UCP2, and UCP3) in 99 young female athletes who had been injured during a sports activity, and we compared the occurrence of muscle traumas with the genotypes using the chi-square test. For the ACTN3 577R allele, the subjects who had non-contact muscle injury had a marked increase in frequency (p-value=0.0015; odds ratio=2.52). The significant increase in non-contact muscle injury related to ACTN3 577R alleles suggests that ACTN3 is likely to be involved in muscle strain and that non-contact muscle injury might occur due to the presence of this allele. It is crucially important for young female athletes to understand their risk for injury, as they might be able to modify their training program to avoid injury, depending on their specific genetic markers.