scholarly journals Nonallelic homologous recombination between retrotransposable elements is a driver of de novo unbalanced translocations

2012 ◽  
Vol 23 (3) ◽  
pp. 411-418 ◽  
Author(s):  
C. Robberecht ◽  
T. Voet ◽  
M. Z. Esteki ◽  
B. A. Nowakowska ◽  
J. R. Vermeesch
Keyword(s):  
Homologous Recombination ◽  
De Novo ◽  
Retrotransposable Elements ◽  
Nonallelic Homologous Recombination

Partial 5p Deletion and Partial 5q Duplication in a Patient with Multiple Congenital Anomalies: A Two-Step Mechanism in Chromosomal Rearrangement Mediated by Non-Allelic Homologous Recombination

2018 ◽  
Vol 156 (2) ◽  
pp. 65-70
Author(s):  
Zhishuo Z. Ou ◽  
Sally Kochmar ◽  
Svetlana A. Yatsenko ◽  
Audrey C. Woerner ◽  
Roxanne Acquaro ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
De Novo ◽  
Chromosome Analysis ◽  
Bioinformatic Analysis ◽  
Deletion Syndrome ◽  
Fish Analysis ◽  
Feeding Difficulties ◽  
Low Copy Repeats ◽  
5P Deletion ◽  
Nonallelic Homologous Recombination

We describe a 5-month-old female who presented with clinical features of 5p deletion syndrome, including high-pitched cry, microcephaly, micrognathia, bilateral preauricular tags, bifid uvula, abnormal palmar creases, bilateral hypoplastic nipples, feeding difficulties, and developmental delay. In addition, the patient also had a cardiac defect, proximal esophageal atresia, and distal tracheoesophageal fistula. aCGH of the patient revealed a 22.9-Mb deletion of chromosome 5p15.33p14.3 and an 8.28-Mb duplication of chromosome 5q12.1q13.2. Parental chromosome analysis indicated that these alterations are de novo. Chromosome and FISH analysis demonstrated that the 5q12.1q13.2 duplicated segment was attached to the 5p14.3 region with the band 5q12.1 more distal to the centromere than the band 5q13.2. Based on the bioinformatic analysis, we postulate a mechanism for the formation of this complex rearrangement of chromosome 5 by 2-step-wise events mediate by nonallelic homologous recombination between low copy repeats. To the best of our knowledge this rearrangement found in our patient has not been reported in the literature. This report demonstrates the value of chromosome analysis in conjunction with FISH and aCGH for identification of complex rearrangements which cannot be revealed by array analysis alone.

Established and Novel Mechanisms Leading to de novo Genomic Rearrangements in the Human Germline

2020 ◽  
Vol 160 (4) ◽  
pp. 167-176 ◽  
Author(s):  
Atsushi Hattori ◽  
Maki Fukami
Keyword(s):  
Structural Changes ◽  
De Novo ◽  
Time Window ◽  
Review Article ◽  
Early Embryogenesis ◽  
Genomic Rearrangements ◽  
Dna Breaks ◽  
Replication Errors ◽  
Double Strand Dna Breaks ◽  
Nonallelic Homologous Recombination

During gametogenesis, the human genome can acquire various de novo rearrangements. Most constitutional genomic rearrangements are created through 1 of the 4 well-known mechanisms, i.e., nonallelic homologous recombination, erroneous repair after double-strand DNA breaks, replication errors, and retrotransposition. However, recent studies have identified 2 types of extremely complex rearrangements that cannot be simply explained by these mechanisms. The first type consists of chaotic structural changes in 1 or a few chromosomes that result from “chromoanagenesis (an umbrella term that covers chromothripsis, chromoanasynthesis, and chromoplexy).” The other type is large independent rearrangements in multiple chromosomes indicative of “transient multifocal genomic crisis.” Germline chromoanagenesis (chromothripsis) likely occurs predominantly during spermatogenesis or postzygotic embryogenesis, while multifocal genomic crisis appears to be limited to a specific time window during oogenesis and early embryogenesis or during spermatogenesis. This review article introduces the current understanding of the molecular basis of de novo rearrangements in the germline.

scholarly journals De novo phosphorylation of H2AX by WSTF regulates transcription-coupled homologous recombination repair

2019 ◽  
Vol 47 (12) ◽  
pp. 6299-6314 ◽  
Author(s):  
Jae-Hoon Ji ◽  
Sunwoo Min ◽  
Sunyoung Chae ◽  
Geun-Hyoung Ha ◽  
Yonghyeon Kim ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Rna Polymerase Ii ◽  
De Novo ◽  
Dna Lesions ◽  
Proliferating Cells ◽  
Histone H2ax ◽  
Rna Transcripts ◽  
Recombination Repair ◽  
Active Transcription

Abstract Histone H2AX undergoes a phosphorylation switch from pTyr142 (H2AX-pY142) to pSer139 (γH2AX) in the DNA damage response (DDR); however, the functional role of H2AX-pY142 remains elusive. Here, we report a new layer of regulation involving transcription-coupled H2AX-pY142 in the DDR. We found that constitutive H2AX-pY142 generated by Williams-Beuren syndrome transcription factor (WSTF) interacts with RNA polymerase II (RNAPII) and is associated with RNAPII-mediated active transcription in proliferating cells. Also, removal of pre-existing H2AX-pY142 by ATM-dependent EYA1/3 phosphatases disrupts this association and requires for transcriptional silencing at transcribed active damage sites. The following recovery of H2AX-pY142 via translocation of WSTF to DNA lesions facilitates transcription-coupled homologous recombination (TC-HR) in the G1 phase, whereby RAD51 loading, but not RPA32, utilizes RNAPII-dependent active RNA transcripts as donor templates. We propose that the WSTF-H2AX-RNAPII axis regulates transcription and TC-HR repair to maintain genome integrity.

scholarly journals A Case of 17q21.31 Microduplication and 7q31.33 Microdeletion, Associated with Developmental Delay, Microcephaly, and Mild Dysmorphic Features

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Adrian Mc Cormack ◽  
Juliet Taylor ◽  
Leah Te Weehi ◽  
Donald R. Love ◽  
Alice M. George
Keyword(s):  
Homologous Recombination ◽  
Developmental Delay ◽  
Microarray Analysis ◽  
Lower Incidence ◽  
Clinical Phenotype ◽  
Microarray Technology ◽  
Dysmorphic Features ◽  
Low Copy Repeats ◽  
Nonallelic Homologous Recombination ◽  
Chromosome Regions

Concurrent cryptic microdeletion and microduplication syndromes have recently started to reveal themselves with the advent of microarray technology. Analysis has shown that low-copy repeats (LCRs) have allowed chromosome regions throughout the genome to become hotspots for nonallelic homologous recombination to take place. Here, we report a case of a 7.5-year-old girl who manifests microcephaly, developmental delay, and mild dysmorphic features. Microarray analysis identified a microduplication in chromosome 17q21.31, which encompasses theCRHR1, MAPT,andKANSL1genes, as well as a microdeletion in chromosome 7q31.33 that is localised within theGRM8gene. To our knowledge this is one of only a few cases of 17q21.31 microduplication. The clinical phenotype of patients with this microduplication is milder than of those carrying the reciprocal microdeletions, and suggests that the lower incidence of the former compared to the latter may be due to underascertainment.

scholarly journals Intrachromosomal mitotic nonallelic homologous recombination is the major molecular mechanism underlying type-2 NF1 deletions

2010 ◽  
Vol 31 (10) ◽  
pp. 1163-1173 ◽  
Author(s):  
Angelika C. Roehl ◽  
Julia Vogt ◽  
Tanja Mussotter ◽  
Antje N. Zickler ◽  
Helene Spöti ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Molecular Mechanism ◽  
Nonallelic Homologous Recombination

The prognostic significance of homologous recombination repair pathway alterations in metastatic hormone-sensitive prostate cancer.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 150-150
Author(s):  
Justin Shaya ◽  
Aaron Lee ◽  
Angelo Cabal ◽  
Justine Panian ◽  
James Michael Randall ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Homologous Recombination ◽  
Cox Regression ◽  
De Novo ◽  
Prognostic Significance ◽  
Parp Inhibitors ◽  
Homologous Recombination Repair ◽  
Significant Difference ◽  
Recombination Repair ◽  
Hormone Sensitive

150 Background: Little is known about the clinical course of patients (pts) with metastatic hormone sensitive prostate cancer (mHSPC) who harbor alterations in the homologous recombination repair (HRR) pathway. Here, we examine the outcomes of men with mHSPC with HRR alterations. Methods: Single center, retrospective analysis of men with mHSPC who underwent next generation sequencing from 2015-2020. The primary endpoint was to assess the time from diagnosis of mHSPC to onset of castrate resistance (mCRPC), as defined by PCWG3 criteria, in pts with HRR alterations vs wild type (WT). Both somatic and germline HRR alterations were permitted. Univariate and multivariate Cox regression were used to assess the effect of HRR alterations on time to mCRPC. Secondary endpoints included time to mCRPC stratified by HRR gene and time to treatment failure (TTF) in HRR altered vs WT pts, stratified by therapy. Results: We identified 151 men with mHSPC for the study. Median age was 66 years and 62% (n = 93) had de novo metastatic disease. 25% (n = 37) had HRR alterations detected and the most common alterations were in BRCA2 (n = 15), ATM (n = 10), CDK12 (n = 7). 78.4% (n = 29) of alterations were somatic and 13.5% (n = 5) of pts had co-alterations in 2 HRR genes. Time to mCRPC was significantly decreased in pts with HRR alterations vs WT (12.7 vs 16.1 mos, HR- 1.95, p- 0.02). In multivariate analysis, the effect of HRR alterations on time to mCRPC remained statistically significant when adjusting for age, mHSPC therapy, presence of visceral metastases, and PSA (adjusted HR- 1.69, p-0.02). Stratified by individual HRR gene, pts with BRCA2, CDK12, or co-occurring alterations had significantly decreased time to mCRPC compared to other HRR alterations (Table). In terms of mHSPC therapy, 45.7% were treated with ADT alone, 27.8% with an androgen receptor signaling inhibitor (ARSI), and 26.5% with docetaxel. TTF was inferior in HRR altered vs WT pts (10.8 vs 13.8 mos, p-0.004, HR- 1.84). Stratified by therapy, TTF was inferior in HRR altered vs WT pts treated with ADT alone (8.9 vs 13.3 mos, p- 0.019, HR-1.94) and there was no significant difference in TTF in HRR altered vs WT pts treated with either the addition of an ARSI or docetaxel. Conclusions: HRR alterations are associated with worsened outcomes in mHSPC patients. Given the established role of PARP inhibitors in mCRPC, these data highlight an opportunity to explore the use of PARP inhibitors in mHSPC to potentially improve outcomes. [Table: see text]

scholarly journals Break-Induced Loss of Heterozygosity in Fission Yeast: Dual Roles for Homologous Recombination in Promoting Translocations and Preventing De Novo Telomere Addition

2007 ◽  
Vol 27 (21) ◽  
pp. 7745-7757 ◽  
Author(s):  
Jason K. Cullen ◽  
Sharon P. Hussey ◽  
Carol Walker ◽  
John Prudden ◽  
Boon-Yu Wee ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Loss Of Heterozygosity ◽  
De Novo ◽  
Strand Break ◽  
Dual Roles ◽  
Dna Double Strand Break ◽  
Break Site ◽  
Break Induced Replication ◽  
End Resection ◽  
Causal Event

ABSTRACT Loss of heterozygosity (LOH), a causal event in tumorigenesis, frequently encompasses multiple genetic loci and whole chromosome arms. However, the mechanisms leading to such extensive LOH are poorly understood. We investigated the mechanisms of DNA double-strand break (DSB)-induced extensive LOH by screening for auxotrophic marker loss ∼25 kb distal to an HO endonuclease break site within a nonessential minichromosome in Schizosaccharomyces pombe. Extensive break-induced LOH was infrequent, resulting from large translocations through both allelic crossovers and break-induced replication. These events required the homologous recombination (HR) genes rad32 +, rad50 +, nbs1 +, rhp51 +, rad22 +, rhp55 +, rhp54 +, and mus81 +. Surprisingly, LOH was still observed in HR mutants, which resulted predominantly from de novo telomere addition at the break site. De novo telomere addition was most frequently observed in rad22Δ and rhp55Δ backgrounds, which disrupt HR following end resection. Further, levels of de novo telomere addition, while increased in ku70Δ rhp55Δ strains, were reduced in exo1Δ rhp55Δ and an rhp55Δ strain overexpressing rhp51. These findings support a model in which HR prevents de novo telomere addition at DSBs by competing for resected ends. Together, these results suggest that the mechanisms of break-induced LOH may be predicted from the functional status of the HR machinery.

scholarly journals Repair of Chromosome Ends after Telomere Loss inSaccharomyces

2001 ◽  
Vol 12 (12) ◽  
pp. 4078-4089 ◽  
Author(s):  
Jeff L. Mangahas ◽  
Mary Kate Alexander ◽  
Lisa L. Sandell ◽  
Virginia A. Zakian
Keyword(s):  
Homologous Recombination ◽  
Base Pair ◽  
De Novo ◽  
Dna Helicase ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Telomeric Dna ◽  
Yeast Chromosome ◽  
Stable Maintenance ◽  
Linear Chromosomes

Removal of a telomere from yeast chromosome VII in a strain having two copies of this chromosome often results in its loss. Here we show that there are three pathways that can stabilize this broken chromosome: homologous recombination, nonhomologous end joining, and de novo telomere addition. Both in a wild-type and a recombination deficient rad52 strain, most stabilization events were due to homologous recombination, whereas nonhomologous end joining was exceptionally rare. De novo telomere addition was relatively rare, stabilizing <0.1% of broken chromosomes. Telomere addition took place at a very limited number of sites on chromosome VII, most occurring close to a 35-base pair stretch of telomere-like DNA that is normally ∼50 kb from the left telomere of chromosome VII. In the absence of the Pif1p DNA helicase, telomere addition events were much more frequent and were not concentrated near the 35-base pair tract of telomere-like DNA. We propose that internal tracts of telomere-like sequence recruit telomerase by binding its anchor site and that Pif1p inhibits telomerase by dissociating DNA primer–telomerase RNA interactions. These data also show that telomeric DNA is essential for the stable maintenance of linear chromosomes in yeast.

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