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Friedman J, Adam S, Arbour L, Armstrong L, Baross A, Birch P, Boerkoel C, Chan S, Chai D, Delaney AD, Flibotte S, Gibson WT, Langlois S, Lemyre E, Li HI, MacLeod P, Mathers J, Michaud JL, McGillivray BC, Patel MS, Qian H, Rouleau GA, Van Allen MI, Yong SL, Zahir FR, Eydoux P, Marra MA. Detection of pathogenic copy number variants in children with idiopathic intellectual disability using 500 K SNP array genomic hybridization. BMC Genomics 2009; 10:526. [PMID: 19917086 PMCID: PMC2781027 DOI: 10.1186/1471-2164-10-526] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 11/16/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Array genomic hybridization is being used clinically to detect pathogenic copy number variants in children with intellectual disability and other birth defects. However, there is no agreement regarding the kind of array, the distribution of probes across the genome, or the resolution that is most appropriate for clinical use. RESULTS We performed 500 K Affymetrix GeneChip array genomic hybridization in 100 idiopathic intellectual disability trios, each comprised of a child with intellectual disability of unknown cause and both unaffected parents. We found pathogenic genomic imbalance in 16 of these 100 individuals with idiopathic intellectual disability. In comparison, we had found pathogenic genomic imbalance in 11 of 100 children with idiopathic intellectual disability in a previous cohort who had been studied by 100 K GeneChip array genomic hybridization. Among 54 intellectual disability trios selected from the previous cohort who were re-tested with 500 K GeneChip array genomic hybridization, we identified all 10 previously-detected pathogenic genomic alterations and at least one additional pathogenic copy number variant that had not been detected with 100 K GeneChip array genomic hybridization. Many benign copy number variants, including one that was de novo, were also detected with 500 K array genomic hybridization, but it was possible to distinguish the benign and pathogenic copy number variants with confidence in all but 3 (1.9%) of the 154 intellectual disability trios studied. CONCLUSION Affymetrix GeneChip 500 K array genomic hybridization detected pathogenic genomic imbalance in 10 of 10 patients with idiopathic developmental disability in whom 100 K GeneChip array genomic hybridization had found genomic imbalance, 1 of 44 patients in whom 100 K GeneChip array genomic hybridization had found no abnormality, and 16 of 100 patients who had not previously been tested. Effective clinical interpretation of these studies requires considerable skill and experience.
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Affiliation(s)
- Jm Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
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Hirst M, Delaney A, Rogers SA, Schnerch A, Persaud DR, O'Connor MD, Zeng T, Moksa M, Fichter K, Mah D, Go A, Morin RD, Baross A, Zhao Y, Khattra J, Prabhu AL, Pandoh P, McDonald H, Asano J, Dhalla N, Ma K, Lee S, Ally A, Chahal N, Menzies S, Siddiqui A, Holt R, Jones S, Gerhard DS, Thomson JA, Eaves CJ, Marra MA. LongSAGE profiling of nine human embryonic stem cell lines. Genome Biol 2008; 8:R113. [PMID: 17570852 PMCID: PMC2394759 DOI: 10.1186/gb-2007-8-6-r113] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 04/23/2007] [Accepted: 06/14/2007] [Indexed: 12/20/2022] Open
Abstract
To facilitate discovery of novel human embryonic stem cell (ESC) transcripts, we generated 2.5 million LongSAGE tags from 9 human ESC lines. Analysis of this data revealed that ESCs express proportionately more RNA binding proteins compared with terminally differentiated cells, and identified novel ESC transcripts, at least one of which may represent a marker of the pluripotent state.
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Affiliation(s)
- Martin Hirst
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Allen Delaney
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Sean A Rogers
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Angelique Schnerch
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Deryck R Persaud
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Michael D O'Connor
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Thomas Zeng
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Michelle Moksa
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Keith Fichter
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Diana Mah
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Anne Go
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Ryan D Morin
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Agnes Baross
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Yongjun Zhao
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Jaswinder Khattra
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Anna-Liisa Prabhu
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Pawan Pandoh
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Helen McDonald
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Jennifer Asano
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Noreen Dhalla
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Kevin Ma
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Stephanie Lee
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Adrian Ally
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Neil Chahal
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Stephanie Menzies
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Asim Siddiqui
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Robert Holt
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Steven Jones
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Daniela S Gerhard
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - James A Thomson
- Wisconsin National Primate Research Centre and Department of Anatomy, School of Medicine, University of Wisconsin, Madison, Wisconsin 53715, USA
| | - Connie J Eaves
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
| | - Marco A Marra
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada, V5Z 1L3
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Zahir FR, Baross A, Delaney AD, Eydoux P, Fernandes ND, Pugh T, Marra MA, Friedman JM. A patient with vertebral, cognitive and behavioural abnormalities and a de novo deletion of NRXN1. J Med Genet 2007; 45:239-43. [DOI: 10.1136/jmg.2007.054437] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Zahir F, Firth HV, Baross A, Delaney AD, Eydoux P, Gibson WT, Langlois S, Martin H, Willatt L, Marra MA, Friedman JM. Novel deletions of 14q11.2 associated with developmental delay, cognitive impairment and similar minor anomalies in three children. J Med Genet 2007; 44:556-61. [PMID: 17545556 PMCID: PMC2597953 DOI: 10.1136/jmg.2007.050823] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
METHODS AND RESULTS We identified de novo submicroscopic chromosome 14q11.2 deletions in two children with idiopathic developmental delay and cognitive impairment. Vancouver patient 5566 has a approximately 200 kb deletion and Vancouver patient 8326 has a approximately 1.6 Mb deletion. The Database of Chromosomal Imbalance and Phenotype in Humans using Ensembl Resources (DECIPHER) revealed a third patient with idiopathic developmental delay and cognitive impairment, DECIPHER patient 126, who has a approximately 1.1 Mb deletion of 14q11.2. The deletion of patient 5566 overlaps that of patient 126 and both of these deletions lie entirely within that of patient 8326. All three children have similar dysmorphic features, including widely-spaced eyes, short nose with flat nasal bridge, long philtrum, prominent Cupid's bow of the upper lip, full lower lip and similar auricular anomalies. CONCLUSION The minimal common deletion region on chromosome 14q11.2 is only approximately 35 kb (from 20.897 to 20.932, University of California at Santa Cruz (UCSC) Genome Browser; build hg18, March 2006) and includes only two genes, SUPT16H and CHD8, which are good candidate genes for the phenotypes. The non-recurrent breakpoints of these patients, the presence of normal copy number variants in the region and the local genomic structure support the notion that this region has reduced stability.
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Affiliation(s)
- Farah Zahir
- Department of Medical Genetics, University of British Columbia, Children's and Women's Hospital, Vancouver, Canada.
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Friedman JM, Baross A, Delaney AD, Ally A, Arbour L, Armstrong L, Asano J, Bailey DK, Barber S, Birch P, Brown-John M, Cao M, Chan S, Charest DL, Farnoud N, Fernandes N, Flibotte S, Go A, Gibson WT, Holt RA, Jones SJM, Kennedy GC, Krzywinski M, Langlois S, Li HI, McGillivray BC, Nayar T, Pugh TJ, Rajcan-Separovic E, Schein JE, Schnerch A, Siddiqui A, Van Allen MI, Wilson G, Yong SL, Zahir F, Eydoux P, Marra MA. Oligonucleotide microarray analysis of genomic imbalance in children with mental retardation. Am J Hum Genet 2006; 79:500-13. [PMID: 16909388 PMCID: PMC1559542 DOI: 10.1086/507471] [Citation(s) in RCA: 225] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Accepted: 07/06/2006] [Indexed: 11/03/2022] Open
Abstract
The cause of mental retardation in one-third to one-half of all affected individuals is unknown. Microscopically detectable chromosomal abnormalities are the most frequently recognized cause, but gain or loss of chromosomal segments that are too small to be seen by conventional cytogenetic analysis has been found to be another important cause. Array-based methods offer a practical means of performing a high-resolution survey of the entire genome for submicroscopic copy-number variants. We studied 100 children with idiopathic mental retardation and normal results of standard chromosomal analysis, by use of whole-genome sampling analysis with Affymetrix GeneChip Human Mapping 100K arrays. We found de novo deletions as small as 178 kb in eight cases, de novo duplications as small as 1.1 Mb in two cases, and unsuspected mosaic trisomy 9 in another case. This technology can detect at least twice as many potentially pathogenic de novo copy-number variants as conventional cytogenetic analysis can in people with mental retardation.
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Affiliation(s)
- J M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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Gerhard DS, Wagner L, Feingold EA, Shenmen CM, Grouse LH, Schuler G, Klein SL, Old S, Rasooly R, Good P, Guyer M, Peck AM, Derge JG, Lipman D, Collins FS, Jang W, Sherry S, Feolo M, Misquitta L, Lee E, Rotmistrovsky K, Greenhut SF, Schaefer CF, Buetow K, Bonner TI, Haussler D, Kent J, Kiekhaus M, Furey T, Brent M, Prange C, Schreiber K, Shapiro N, Bhat NK, Hopkins RF, Hsie F, Driscoll T, Soares MB, Casavant TL, Scheetz TE, Brown-stein MJ, Usdin TB, Toshiyuki S, Carninci P, Piao Y, Dudekula DB, Ko MSH, Kawakami K, Suzuki Y, Sugano S, Gruber CE, Smith MR, Simmons B, Moore T, Waterman R, Johnson SL, Ruan Y, Wei CL, Mathavan S, Gunaratne PH, Wu J, Garcia AM, Hulyk SW, Fuh E, Yuan Y, Sneed A, Kowis C, Hodgson A, Muzny DM, McPherson J, Gibbs RA, Fahey J, Helton E, Ketteman M, Madan A, Rodrigues S, Sanchez A, Whiting M, Madari A, Young AC, Wetherby KD, Granite SJ, Kwong PN, Brinkley CP, Pearson RL, Bouffard GG, Blakesly RW, Green ED, Dickson MC, Rodriguez AC, Grimwood J, Schmutz J, Myers RM, Butterfield YSN, Griffith M, Griffith OL, Krzywinski MI, Liao N, Morin R, Morrin R, Palmquist D, Petrescu AS, Skalska U, Smailus DE, Stott JM, Schnerch A, Schein JE, Jones SJM, Holt RA, Baross A, Marra MA, Clifton S, Makowski KA, Bosak S, Malek J. The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome Res 2004; 14:2121-7. [PMID: 15489334 PMCID: PMC528928 DOI: 10.1101/gr.2596504] [Citation(s) in RCA: 403] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.
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Baross A, Butterfield YSN, Coughlin SM, Zeng T, Griffith M, Griffith OL, Petrescu AS, Smailus DE, Khattra J, McDonald HL, McKay SJ, Moksa M, Holt RA, Marra MA. Systematic recovery and analysis of full-ORF human cDNA clones. Genome Res 2004; 14:2083-92. [PMID: 15489330 PMCID: PMC528924 DOI: 10.1101/gr.2473704] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Mammalian Gene Collection (MGC) consortium (http://mgc.nci.nih.gov) seeks to establish publicly available collections of full-ORF cDNAs for several organisms of significance to biomedical research, including human. To date over 15,200 human cDNA clones containing full-length open reading frames (ORFs) have been identified via systematic expressed sequence tag (EST) analysis of a diverse set of cDNA libraries; however, further systematic EST analysis is no longer an efficient method for identifying new cDNAs. As part of our involvement in the MGC program, we have developed a scalable method for targeted recovery of cDNA clones to facilitate recovery of genes absent from the MGC collection. First, cDNA is synthesized from various RNAs, followed by polymerase chain reaction (PCR) amplification of transcripts in 96-well plates using gene-specific primer pairs flanking the ORFs. Amplicons are cloned into a sequencing vector, and full-length sequences are obtained. Sequences are processed and assembled using Phred and Phrap, and analyzed using Consed and a number of bioinformatics methods we have developed. Sequences are compared with the Reference Sequence (RefSeq) database, and validation of sequence discrepancies is attempted using other sequence databases including dbEST and dbSNP. Clones with identical sequence to RefSeq or containing only validated changes will become part of the MGC human gene collection. Clones containing novel splice variants or polymorphisms have also been identified. Our approach to clone recovery, applied at large scale, has the potential to recover many and possibly most of the genes absent from the MGC collection.
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Affiliation(s)
- Agnes Baross
- Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia, V5Z 4E6, Canada
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Cheung I, Schertzer M, Baross A, Rose AM, Lansdorp PM, Baird DM. Strain-specific telomere length revealed by single telomere length analysis in Caenorhabditis elegans. Nucleic Acids Res 2004; 32:3383-91. [PMID: 15247331 PMCID: PMC443537 DOI: 10.1093/nar/gkh661] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Terminal restriction fragment analysis is the only method currently available for measuring telomere length in Caenorhabditis elegans. Its limitations include low sensitivity and interference by the presence of interstitial telomeric sequences in the C.elegans genome. Here we report the adaptation of single telomere length analysis (STELA) to measure the length of telomeric repeats on the left arm of chromosome V in C.elegans. This highly sensitive PCR-based method allows telomere length measurement from as few as a single worm. The application of STELA to eight wild-type C.elegans strains revealed considerable strain-specific differences in telomere length. Within individual strains, short outlying telomeres were observed that were clearly distinct from the bulk telomere length distributions, suggesting that processes other than end-replication losses and telomerase-mediated lengthening may generate telomere length heterogeneity in C.elegans. The utility of this method was further demonstrated by the characterization of telomere shortening in mrt-2 mutants. We conclude that STELA appears to be a valuable tool for studying telomere biology in C.elegans.
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Affiliation(s)
- Iris Cheung
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC V5Z 4E6, Canada
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Baross A, Schertzer M, Zuyderduyn SD, Jones SJM, Marra MA, Lansdorp PM. Effect of TERT and ATM on gene expression profiles in human fibroblasts. Genes Chromosomes Cancer 2004; 39:298-310. [PMID: 14978791 DOI: 10.1002/gcc.20006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Telomeres protect chromosomes from degradation, end-to-end fusion, and illegitimate recombination. Loss of telomeres may lead to cell death or senescence or may cause genomic instability, leading to tumor formation. Expression of human telomerase reverse transcriptase (TERT) in human fibroblast cells elongates their telomeres and extends their lifespan. Ataxia telangiectasia mutated (ATM) deficiency in A-T human fibroblasts results in accelerated telomere shortening, abnormal cell-cycle response to DNA damage, and early senescence. Gene expression profiling was performed by serial analysis of gene expression (SAGE) on BJ normal human skin fibroblasts, A-T cells, and BJ and A-T cells transduced with TERT cDNA and expressing telomerase activity. In the four SAGE libraries, 36,921 unique SAGE tags were detected. Pairwise comparisons between the libraries showed differential expression levels of 1%-8% of the tags. Transcripts affected by both TERT and ATM were identified according to expression patterns, making them good candidates for further studies of pathways affected by both TERT and ATM. These include MT2A, P4HB, LGALS1, CFL1, LDHA, S100A10, EIF3S8, RANBP9, and SEC63. These genes are involved in apoptosis or processes related to cell growth, and most have been found to be deregulated in cancer. Our results have provided further insight into the roles of TERT and ATM by identifying genes likely to be involved in their function. Supplementary material for this article can be found on the Genes, Chromosomes and Cancer website at http://www.interscience.wiley.com/jpages/1045-2257/suppmat/index.html.
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Affiliation(s)
- Agnes Baross
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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Mark SC, Sandercock LE, Luchman HA, Baross A, Edelmann W, Jirik FR. Elevated mutant frequencies and predominance of G:C to A:T transition mutations in Msh6(-/-) small intestinal epithelium. Oncogene 2002; 21:7126-30. [PMID: 12370835 DOI: 10.1038/sj.onc.1205861] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2002] [Revised: 07/03/2002] [Accepted: 07/09/2002] [Indexed: 01/18/2023]
Abstract
The DNA mismatch repair (MMR) system is primarily responsible for purging newly synthesized DNA of errors incurred during semi-conservative replication. Lesion recognition is initially carried out by one of two heterodimeric protein complexes, MutS(alpha) or MutS(beta). While the former, comprised of MSH2 and MSH6, recognizes mispairs as well as short (1-2 nucleotide) insertions/deletions (IDLs), the latter, made up of MSH2 and MSH3, is primarily responsible for recognizing 2-6 nucleotide IDLs. As most of the functional information on these heterodimers is derived from in vitro studies, it was of interest to study the in vivo consequences of a lack of MutS(alpha). To this end, Big Blue( trade mark ) mice, that carry a lacI(+) transgenic lambda shuttle-phage mutational reporter, were crossed with Msh6(-/-) mice to evaluate the specific contribution of MutS(alpha) to genome integrity. Consistent with the importance of MutS(alpha) in lesion surveillance, small intestine epithelial cell DNA derived from lacI(+) Msh6(-/-) mice exhibited striking increases (average of 41-fold) in spontaneous mutant frequencies. Furthermore, the lacI gene mutation spectrum was dominated by G:C to A:T transitions, highlighting the critical importance of the MutS(alpha) complex in suppressing this frequently observed type of spontaneous mutation.
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Affiliation(s)
- Sean C Mark
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4N1
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