Coaction of DNA topoisomerase IIIalpha and a RecQ homologue during the germ-line mitosis in Caenorhabditis elegans

Among the four RecQ homologues predicted from the Caenorhabditis elegans genomic DNA sequence, T04A11.6 is most similar to Bloom syndrome's protein in humans. To investigate a possible interaction of the protein with topoisomerase IIIalpha (TOP3alpha), as observed between TOP3 and RecQ homologu...

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Bibliographic Details
Published in:Genes to cells : devoted to molecular & cellular mechanisms 2002-01, Vol.7 (1), p.19-27
Main Authors: Kim, You-Chan, Lee, Min-Ho, Ryu, Sung-Shin, Kim, Ji-Hoon, Koo, Hyeon-Sook
Format: Article
Language:English
Subjects:
Adenosine Triphosphatases - metabolism
Animals
Caenorhabditis elegans - cytology
Caenorhabditis elegans - physiology
Chromosome Aberrations
DNA Helicases - metabolism
DNA Topoisomerases, Type I - metabolism
Germ Cells - physiology
Meiosis - physiology
Mitosis - physiology
Protein Binding
RecQ Helicases
RNA - immunology
RNA - metabolism
RNA - physiology
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Summary:Among the four RecQ homologues predicted from the Caenorhabditis elegans genomic DNA sequence, T04A11.6 is most similar to Bloom syndrome's protein in humans. To investigate a possible interaction of the protein with topoisomerase IIIalpha (TOP3alpha), as observed between TOP3 and RecQ homologues in yeast and human, the top3alpha gene expression was suppressed by RNA interference (RNAi) in the him-6(e1104) C. elegans strain which is mutated in T04A11.6 (F. Mueller & C. Wicky, personal communication). Germ cells in the gonads of the progeny him-6(e1104);top3alpha(RNAi) showed severe chromosomal abnormalities and were arrested during mitosis with a subsequent failure in meiotic entry. Most of the aberrant chromosomes were stained by the TUNEL assay but not by the SYTO12 dye, suggesting extensive DNA breaks not associated with apoptosis. The phenotypes in the germ cells of him-6(e1104);top3alpha(RNAi) were also observed in the progeny produced by double RNA interference of the top3alpha and him-6 gene expression, though at a reduced level. The over-expressed TOP3alpha and Him-6 proteins showed specific physical interaction in vitro, in agreement with the genetic interaction in C. elegans. In C. elegans, TOP3alpha and the RecQ homologue (T04A11.6) contribute to genome stability during germ-line mitosis, probably by acting in a complex.
ISSN:1356-9597