Genetic engineering technology has been contributing to human life. The first generation of genetic engineering to cut and join DNA fragments in vitro and to introduce it to the living cells was invented in the 1970s. By this technique, specific DNA can be artificially amplified to be manipulated. Research for understanding the fundamental mechanisms of life, including DNA replication, repair, and recombination, has led to the discovery of enzymes acting on DNA, resulting in developing gene manipulation techniques to cut and paste DNA in vitro. Research on thermostable DNA polymerases has led to practical application of PCR technology. The genome editing technology using the RNA-inducible nuclease in CRISPR-Cas9 system is now spreading rapidly due to its high convenience and reliability. In this seminar, I will overview the 40-year histry of genetic engineering enzymes and will introduce some of our successful examples for the development of useful enzymes.
DNA polymerase capable of synthesizing a DNA chain in vitro is an essential enzyme for DNA sequencing and PCR, and its market value is especially high as a star enzyme in the genetic Engineering field. In addition, improving the function of DNA polymerase also leads to the development of new technology. I will introduce successful examples of protein engineering that succeeded in imparting higher extension ability and stronger chain substitution activity to Taq DNA polymerase, which is the most popular PCR enzyme. Created enzymes will expand the range of PCR applications and will also contribute to the expansion of gene amplification technology utilizing strand displacement activity. Furthermore, these successes not only provide practical new enzymes, but also serve as structural and functional information to better understanding of the nature of DNA polymerases. Nucleases also play important roles in technology development. We have continuously discovered the nucleases with unique substrate specificity. I will summarize these enzymes, including Hjc, Hef, HAN, ExoI, EndoQ and EndoMS, found in the hyperthermophilic archaea.
I. DNA replication and recombinational repair in Archae
II. Application of the DNA-related enzymes to genetic engineering techniques
III. Marine metagenomic analysis to monitor sea environment