2001 Fiscal Year Final Research Report Summary

Cloning of new endonuclease (AN34) involved in apoptosis.

Research Project

Project/Area Number	11670988
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Hematology
Research Institution	Fukui Medical University
Principal Investigator	YOSHIDA Akira Fukui Medical University, Dept. of Medicine, Assistant Professor, 医学部, 助手 (80252005)
Project Period (FY)	1999 – 2001
Keywords	Apoptosis / endonuclease / AN34
Research Abstract	We previously purified an apoptotic nuclease 34kDa (AN34) from human leukemia HL-60 cells (Cancer Res 58,1998). AN34 is a Mg2+ dependent endonuclease which induces DNA single and double strand breaks. In this study, we investigated whether AN34 is regulated by caspase 3 using cell-free system and chromatography. AN34 was purified from HL-60 cell lysate which was preincubated with recombinant caspase 3. DFF40/CAD was also separated from caspase 3 treated cell lysate at different fraction of ion exchange column. However, we could not isolate AN34 and DFF40/CAD from non-treated cell lysates. We compared biochemical property of AN34 with DFF40/CAD. AN34 predominantly induces DNA single strand breaks. On the other hand, DFF40/CAD induces mainly DNA doubles strand breaks. In addition, AN34 showed not only endonuclease activity but also strong 3'-5'exonuclease activity. These data indicate that AN34 is a unique caspase 3 regulated 3'-5'exo-endonuclease which shows distinct biochemical property from DFF40/CAD.