Takashi Horiuchim his areas of research interest is Genome Dynamics, especially the physiological role in DNA replication fork blocking events in E. coli and S. cerevisiae, successful conversion from the circular genome of E. coli to linear, molecular mechanism of gene amplification of rDNA in yeast and oncogene (drug-resistant gene) in higher eukaryotes, and molecular mechanism of DRCR (Double Rolling Circular Replication) in Herpes Simplex Virus (HSV) and Chloroplast DNA. Dr. Horiuchi got Kihara Prize (2007) from Japan Society of Genetics for “Identification and characterization of DNA replication fork blocking event


It is well established that eukaryote nuclear chromosomes are duplicated from multiple origins of replication. It remains a mystery, however, how genomes of some viruses, such as HSV (Herpes simplex virus) and Baculovirus, or chroloplasts, are replicated. We found recently that (i) double rolling circle replication (DRCR), originally found responsible for replication of yeast 2 micron plasmid DNA, can lead to amplification of oncogenes as well as drug resistance genes, and (ii) that DRCR is highly recombinogenic. In addition, we will present our model, based on these findings, that DRCR is involved in DNA replication of HSV-1, chloroplasts and some mitochondria. The model could explain how DRCR contributes to replication-recombination coupling of HSV, and also how it promote amplicon shortening during gene amplification. HO induced