0172239 - UEB-Q 20023018 RIV GB eng J - Journal Article
Hartung, F. - Angelis, Karel - Meister, A.
An Archaebacterial Topoisomerase Homolog Not Present in Other Eukaryotes Is Indispensable for Cell Proliferation of Plants.
Current Biology. Roč. 12, - (2002), s. 1787-1791. ISSN 0960-9822. E-ISSN 1879-0445
R&D Projects: GA AV ČR IAA6038201; GA ČR GA521/01/1418
Institutional research plan: CEZ:AV0Z5038910
Keywords : Archaebacterial Topoisomerase * Cell Proliferation
Subject RIV: GE - Plant Breeding
Impact factor: 7.007, year: 2002

Plants, in contrast to other eukaryotes, possess not only homologs of subunit A (AISPO11-1, 2,3) but also of subunit B (AITOP6B) of the archaebacterial topo-isomerase VI [1]. AITOP6B and AtSPOl 1 -3 are strongly expressed in somatic tissue of Arabidopsis and are able to interact with each other in vitro. A T-DNA insertion in AtTOP6B results in deficient cell proliferation; plants stop growing at the rosette stage, have small crinkled leaves, and die about 4 weeks after germination. Cultured root cells die after a limited number of cell divisions. The mitotic index of the root meristems is strongly reduced. Flow cytometric analysis demonstrates that endoreplication in mutant plants is stopped at the 8C stage; the last cycle is not completed in most cases. Mutant plants show a significant increase in nuclear DNA strand breaks. A T-DNA insertion mutant of AtSPO11-3 has a phenotype that is almost to that of AtTOPSB and the double mutant. Thus, both genes seem to act in vivo as subunits of a functional entity.
Permanent Link: http://hdl.handle.net/11104/0069278