PANTHER family review PTHR13710: IBA propagation assessment for rqh1
OpenScientist hypothesis report: direct four-way-junction helicase activity of S. pombe Rqh1
Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Automatic Gene Ontology annotation based on Rhea mapping
Electronic Gene Ontology annotations created by ARBA machine learning models
Combined Automated Annotation using Multiple IEA Methods
Cdc2-cyclin B kinase activity links Crb2 and Rqh1-topoisomerase III.
-
Rqh1, in association with Top3, processes recombination intermediates during G2 HR repair of radiation-induced DSBs, acting after Rhp51 focus assembly and regulated by Cdc2-cyclin B via Crb2.
"low Cdc2-cyclin B activity prevents the proper regulation of topoisomerase III (Top3) function, disrupting a recombination step that occurs after the assembly of Rhp51 foci."
Helicase activity is only partially required for Schizosaccharomyces pombe Rqh1p function.
-
Rqh1p is biochemically a 3'-5' DNA helicase, but its helicase activity is only partially required for recovery from S-phase arrest or DNA damage.
"Here we show that, like other RecQ family members, the Rqh1p protein displays 3' to 5' DNA helicase activity. Interestingly, however, unlike other RecQ family members, the helicase activity of Rqh1p is only partially required for its function in recovery from S-phase arrest or DNA damage."
Role for the fission yeast RecQ helicase in DNA repair in G2.
-
Rqh1 is the single S. pombe RecQ homolog, a 3'-5' helicase that exists with Top3 in a high-MW complex and functions after Rad51 focus formation in G2 DNA repair.
"We show that Rqh1, the single Schizosaccharomyces pombe homologue, is a 3'-to-5' helicase and exists with Top3 in a high-molecular-weight complex."
Slx1-Slx4 are subunits of a structure-specific endonuclease that maintains ribosomal DNA in fission yeast.
-
Deletion of Rqh1 causes rDNA contraction and is synthetically lethal with the Slx1-Slx4 endonuclease, implicating Rqh1 in rDNA maintenance at replication fork barriers.
"Deletion of Slx1 or Rqh1 RecQ-like DNA helicase provokes rDNA contraction, whereas simultaneous elimination of Slx1-Slx4 endonuclease and Rqh1 is lethal."
The N-terminal region of the Schizosaccharomyces pombe RecQ helicase, Rqh1p, physically interacts with Topoisomerase III and is required for Rqh1p function.
-
Top3 binds within the first 322 N-terminal residues of Rqh1, and this interaction correlates with Rqh1 function.
"Topoisomerase III (Top3) binds to a site within the first 322 N-terminal amino acids of Rqh1 and that this binding correlates with Rqh1 function."
Replication fork blockage by RTS1 at an ectopic site promotes recombination in fission yeast.
-
Rqh1 prevents blocked replication forks from collapsing into one-sided DSBs and deletions at the RTS1 fork barrier.
"In the absence of the RecQ family DNA helicase Rqh1, deletion events increase dramatically, which correlates with the detection of one-sided DNA double-strand breaks at or near RTS1. These data indicate that Rqh1 acts to prevent blocked replication forks from collapsing and thereby inducing deletion events."
Role of the Schizosaccharomyces pombe F-Box DNA helicase in processing recombination intermediates.
-
The Fbh1 F-box helicase is synthetically lethal with rqh1 (and srs2), suppressed by rhp57 deletion, indicating overlapping roles in processing toxic Rhp51-dependent recombination intermediates.
"fbh1 is essential for viability in stationary-phase cells and in the absence of either Srs2 or Rqh1 DNA helicase. In each case, lethality is suppressed by deletion of the recombination gene rhp57."
A role for the fission yeast Rqh1 helicase in chromosome segregation.
-
rqh1 deletion delays anaphase and produces lagging chromosomal DNA, especially at rDNA; the Top3-RecQ complex maintains rDNA structure by processing replication-derived aberrant structures.
"These data are consistent with the function of the Top3-RecQ complex in maintenance of the rDNA structure by processing aberrant chromosome structures arising from DNA replication."
Mus81, Rhp51(Rad51), and Rqh1 form an epistatic pathway required for the S-phase DNA damage checkpoint.
-
Mus81, Rhp51 and Rqh1 form an epistatic pathway downstream of Cds1 required for slowing replication in response to S-phase DNA damage, with Rqh1 restraining recombination.
"We have identified proteins downstream of Cds1 required for checkpoint-dependant slowing, including the structure-specific endonuclease Mus81 and the helicase Rqh1, which are implicated in replication fork stability and the negative regulation of recombination."
Release of Ku and MRN from DNA ends by Mre11 nuclease activity and Ctp1 is required for homologous recombination repair of double-strand breaks.
-
Rqh1 (Sgs1 ortholog) plays a minor role supporting Exo1-dependent long-range end resection at DSBs in fission yeast.
"Exo1 is largely responsible for extended resection up to 3.1 kb from a DSB, with an activity dependent on Rqh1 (Sgs1) DNA helicase having a minor role."
Recovery of arrested replication forks by homologous recombination is error-prone.
-
Rqh1 limits gross chromosomal rearrangements at collapsed forks by preventing inappropriate ectopic recombination during HR-mediated fork recovery.
"Rqh1 limits GCRs at collapsed forks by preventing inappropriate ectopic recombination during the process of fork recovery by recombination proteins."
The chromatin assembly factor 1 promotes Rad51-dependent template switches at replication forks by counteracting D-loop disassembly by the RecQ-type helicase Rqh1.
-
Rqh1 disassembles D-loops formed during Rad51-dependent template switching at blocked forks; CAF-1 antagonizes this disassembly.
"We establish that CAF-1 promotes template switch by counteracting D-loop disassembly by Rqh1."
Factors affecting template switch recombination associated with restarted DNA replication.
-
Rqh1, together with Fbh1 and Srs2, strongly suppresses template switching during recombination-restarted DNA replication.
"A further three conserved helicases (Fbh1, Rqh1 and Srs2) strongly suppress TS, but there is no change in TS frequency in cells lacking Fml1 or Mus81."
An alternative eukaryotic DNA excision repair pathway.
-
The rad12-502 mutant (later identified as rqh1) was reported to lack SPDE UV-dimer endonuclease activity in an excision-repair pathway distinct from NER; this excision activity was subsequently not attributable to the RecQ helicase.
"Here we report that the UV-sensitive S. pombe rad12-502 mutant lacks SPDE activity."
Role of Schizosaccharomyces pombe RecQ homolog, recombination, and checkpoint genes in UV damage tolerance.
-
rad12-502 and hus2.22 are alleles of the recQ homolog rqh1; Rqh1 acts in S phase in a recombination/checkpoint-dependent DNA damage survival (tolerance) mechanism, and rqh1 mutants are not defective in UV dimer endonuclease activity.
"in contrast with the reported literature, we do not find that rqh1 (rad12) mutant cells are defective in UV dimer endonuclease activity."