Čeština
EnglishAn Archaebacterial Topoisomerase Homolog Not Present in Other Eukaryotes Is Indispensable for Cell Proliferation of Plants
Hartung F., Angelis K.J., Meister A., Schubert I., Melzer M., Puchta H.
CURRENT BIOLOGY 12: 1787-1791, 2002
Klíčová slova:
Abstrakt: Plants, in contrast to other eukaryotes, possess not only homologs of subunit A (AtSPO11-1, 2, 3) but also of subunit B (AtTOP6B) of the archaebacterial topoisomerase VI. AtTOP6B and AtSPO11-3 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 AtTOP6B and the double mutant. Thus, both genes seem to act in vivo as subunits of a functional entity. A loss of this function most likely results in a defect in DNA replication, leading directly, or via the activation of a DNA damage checkpoint, to an arrest of cell division and endoreduplication. The dependence on an archaebacterial topoisomerase VI homolog distinguishes plants from the other eukaryotic kingdoms.
DOI:
Autoři z ÚEB: Karel J. Angelis
CURRENT BIOLOGY 12: 1787-1791, 2002
Klíčová slova:
Abstrakt: Plants, in contrast to other eukaryotes, possess not only homologs of subunit A (AtSPO11-1, 2, 3) but also of subunit B (AtTOP6B) of the archaebacterial topoisomerase VI. AtTOP6B and AtSPO11-3 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 AtTOP6B and the double mutant. Thus, both genes seem to act in vivo as subunits of a functional entity. A loss of this function most likely results in a defect in DNA replication, leading directly, or via the activation of a DNA damage checkpoint, to an arrest of cell division and endoreduplication. The dependence on an archaebacterial topoisomerase VI homolog distinguishes plants from the other eukaryotic kingdoms.
DOI: