Institute for Molecular and Cellular Biology
HOMEResearch Divisions

Section of Cell Structure and Function Division of Cellular Biology (Prof. Hanaoka)

Proffessor HANAOKA,Fumio,D.Pharm. TEL 06-6879-7975
Associate Prof. OHKUMA,Yoshiaki,D.Pharm.   FAX 06-6877-9382
Assistant Prof. MASUTANI,Chikahide,D.Pharm.   E-mail fhanaoka@imcb.osaka-u.ac.jp
Assistant Prof. YOKOI, Masayuki, Ph.D.      

Major projects engaged in by this Division are:

1 Molecular mechanism of nucleotide excision repair.

In the course of evolution, living organisms acquired various kinds of DNA repair mechanism. Nucleotide excision repair is one of the most versatile DNA repair systems, which eliminates a wide variety of DNA damage. We constructed a cell-free DNA repair system with UV-irradiated SV40 minichromosomes as templates. Using this system, we are trying toæpurify proteins involved in nucleotide excision repair in mammalian cells and to clarify the mode of actions of these protein factors.

2 Studies on general transcription factors.

Eukaryotic transcription is supported by three distinct RNA polymerases and, especially, RNA polymerase II (Pol II) involves in gene expression. Through the analyses of the general transcription factor TFIIH, which involves coodinative regulation between Pol II transcription and nucleotide excision repair, and another general transcription factor TFIIE that regulates TFIIH, we have been studying molecular mechanisms of transcription and repair.

3 Mechanisms of chromosome replication.

DNA replication is the most fundamental process for cell duplication and locates in the center of cell cycle. We have been analyzing the structure and function of mammalian DNA polymerase α.Transcriptional regulation during the cell cycle of genes for DNA polymerase α subunits is also investigated. In addition, we are working on a novel DNA polymerase which can bypass DNA damages.

  Three Step Model for Transcription Initiation

At the first step, before transcription initiation, the promoter DNA is opened in the preinitiation complex. At the second step, DNA opening expands to downstream during transcription initiation. At the third step, Pol II forms an elongation complex and moves downstream together with opened DNA position. The abbreviations: B,TFIIB; D,TFIID; E,TFIIE; F,TFIIF; H,TFIIH; Pol IIA, hypophosphorylated Pol II; Pol IIO, phosphorylated Pol II.

  Damage Recognition and Initiation of Nucleotide Excision Repair by XPC Protein Complex

In combination with DNase I footprinting, DNA damage recognition-competition assay, and coimmunoprecipitation assay, we clearly demonstrated that XPC-hHR23B plays a central role in damage detection and initiation of the NER reaction.

Publications

HOMEResearch Divisions

(C) 2002 Osaka University Institute for Molecular and Cellular Biology