Dr Mutsuo Sekiguchi obtained his doctor degree from Osaka University, Japan, and conducted his postdoctoral works in biochemistry and molecular genetics at Kanazawa University Medical School, Kanazawa, Japan, University of Pennsylvania School of Medicine, Philadelphia, and Purdue University, Indiana, USA, under the guidance of Drs Y Takagi, SS Cohen and S Benzer, respectively. Dr Sekiguchi became Associate Professor of Biochemistry at Kyushu University School of Medicine, Fukuoka, Japan, in 1965 and started his work on molecular mechanisms of DNA repair. He and his colleagues discovered T4 endonuclease V, one of the first DNA repair enzymes functioning in vivo to repair UV-damaged DNA without the aid of visible light. Dr Sekiguchi extended his works on enzymic repair of chemically damaged DNA and control mechanisms for spontaneous mutagenesis, some of which are dealt with in articles in this issue. Dr Sekiguchi was Professor of Molecular Genetics and Biochemistry at Kyushu University (1969–1996) and subsequently at Fukuoka Dental College. He was also Director of the Medical Institute of Bioregulation, Kyushu University from 1992–1996. He is presently Director of the Biomolecular Engineering Research Institute, an independent research organization, which is located in Osaka, Japan, and operated by support of both the Japanese Government (Ministry of Economy, Trade and Industry) and major industrial companies. This photograph was taken in the lobby of the Institute, alongside the molecular model of T4 endonuclease V, which was determined by Dr K Morikawa and associates at the Institute.

figure 1

Figure 1