title: DmGEN, a novel RAD2 family endo-exonuclease from Drosophila melanogaster.
abstract: A novel endo-exonuclease, DmGEN (Drosophila Melanogaster XPG-like endonuclease), was identified in D.melanogaster. DmGEN is composed of five exons and four introns, and the open reading frame encodes a predicted product of 726 amino acid residues with a molecular weight of 82.5 kDa and a pI of 5.36. The gene locus on Drosophila polytene chromosomes was detected at 64C9 on the left arm of chromosome 3 as a single site. The encoded protein showed a relatively high degree of sequence homology with the RAD2 nucleases, especially XPG. Although the XPG-N- and XPG-I-domains are highly conserved in sequence, locations of the domains are similar to those of FEN-1 and EXO-1, and the molecular weight of the protein is close to that of EXO-1. In vitro, DmGEN showed endonuclease and 3'-5' exonuclease activities with both single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA), but the endonuclease action with dsDNA was quite specific: 5'-3' exonuclease activity was found to occur with nicked DNA, while dsDNA was endonucleolytically cut at 3-4 bp from the 5' end. Homologs are widely found in mammals and higher plants. The data suggest that DmGEN belongs to a new class of RAD2 nuclease.
authors.affiliation: Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-Shi, Chiba-ken 278 8510, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Ishikawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kanai
authors.forename: Kei-ichi
authors.initials: K
authors.lastname: Takata
authors.forename: Ryo
authors.initials: R
authors.lastname: Takeuchi
authors.forename: Kaori
authors.initials: K
authors.lastname: Shimanouchi
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Ruike
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Furukawa
authors.forename: Seisuke
authors.initials: S
authors.lastname: Kimura
authors.forename: Kengo
authors.initials: K
authors.lastname: Sakaguchi
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D029721:Drosophila Proteins / Q000737:chemistry / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000201:enzymology*; D004706:Endodeoxyribonucleases / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D004720:Endonucleases / Q000737:chemistry / Q000145:classification* / Q000235:genetics*; D005090:Exodeoxyribonucleases / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D029721:Drosophila Proteins; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D005090:Exodeoxyribonucleases; C494357:GEN protein, Drosophila