Molecular characterization of homologues of both subunits A (SPO11) and B of the archaebacterial topoisomerase 6 in plants.
The Spo11 protein is an eukaryotic homologue of the topoisomerase 6 subunit A from archaebacteria. In yeast Spo11p has been found to bind covalently to double-strand breaks (DSBs) during meiosis. Single homologues of the SPO11 gene exist in various eukaryotes, except plants. Previously, we found in the Arabidopsis thaliana genome two ancient paralogs, AtSPO11-1 and 2. Here we report on the molecular characterization of a third one, AtSPO11-3. This puzzling finding might be explained by the fact that we detected additionally--for the first time outside of the archaebacterial kingdom--a homologue of the subunit B of topoisomerase 6, AtTOP6B. Both AtSPO11-3 and AtTOP6B are abundantly expressed in Arabidopsis and EST comparisons indicate the presence of both genes in various plant species. Via two hybrid studies we could demonstrate that full length AtTop6B is able to interact with AtSpo11-2 and 3 but not with AtSpo11-1. Our data suggest that plants possess in contrast to other eukaryotes an additional archaebacterial kind of topoisomerase.
Hartung
F
F
Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany.
Puchta
H
H
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D019843:Archaeal Proteins; D026942:DNA Topoisomerases / Q000235:genetics*; D004250:DNA Topoisomerases, Type II / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004706:Endodeoxyribonucleases; D004950:Esterases / Q000235:genetics* / Q000378:metabolism; D020224:Expressed Sequence Tags; D008969:Molecular Sequence Data; D010944:Plants / Q000235:genetics; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D000099257:Meiotic Recombination Protein SPO11
D029681:Arabidopsis Proteins; D019843:Archaeal Proteins; D026942:DNA Topoisomerases; D004250:DNA Topoisomerases, Type II; D018076:DNA, Complementary; D004706:Endodeoxyribonucleases; D004950:Esterases; D020033:Protein Isoforms; D021122:Protein Subunits; D012333:RNA, Messenger; D000099257:Meiotic Recombination Protein SPO11; C105141:DNA topoisomerase VI; C515047:SPO11-3 protein, Arabidopsis