RecQ promotes toxic recombination in cells lacking recombination intermediate-removal proteins.
The RecQ-helicase family is widespread, is highly conserved, and includes human orthologs that suppress genomic instability and cancer. In vivo, some RecQ homologs promote reduction of steady-state levels of bimolecular recombination intermediates (BRIs), which block chromosome segregation if not resolved. We find that, in vivo, E. coli RecQ can promote the opposite: the net accumulation of BRIs. We report that cells lacking Ruv and UvrD BRI-resolution and -prevention proteins die and display failed chromosome segregation attributable to accumulation of BRIs. Death and segregation failure require RecA and RecF strand exchange proteins. FISH data show that replication is completed during chromosome-segregation failure/death of ruv uvrD recA(Ts) cells. Surprisingly, RecQ (and RecJ) promotes this death. The data imply that RecQ promotes the net accumulation of BRIs in vivo, indicating a second paradigm for the in vivo effect of RecQ-like proteins. The E. coli RecQ paradigm may provide a useful model for some human RecQ homologs.
Magner
Daniel B
DB
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
Blankschien
Matthew D
MD
Lee
Jennifer A
JA
Pennington
Jeanine M
JM
Lupski
James R
JR
Rosenberg
Susan M
SM
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D042522:DNA Replication Timing; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D008954:Models, Biological; D009154:Mutation; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D053484:RecQ Helicases / Q000378:metabolism*; D011995:Recombination, Genetic; D013696:Temperature
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C061260:RuvB protein, Bacteria; C489340:recF protein, E coli; C069806:ruvC protein, E coli; D011938:Rec A Recombinases; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C489467:RecJ protein, E coli; C071059:Holliday junction DNA helicase, E coli; C506724:RecQ protein, E coli; C506746:UvrD protein, E coli; D004265:DNA Helicases; D053484:RecQ Helicases