| 1. |
- Charbonnier, FC, et al.
(författare)
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The 5 ' Region of the MSH2 gene involved in hereditary non-polyposis colorectal cancer contains a high density of recombinogenic sequences
- 2005
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 26:3, s. 255-261
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Tidskriftsartikel (refereegranskat)abstract
- MSH2 rearrangements are involved in approximately 10% of hereditary non,polyposis colorectal cancer (HNPCC) families, and in most of the rearrangements, exon I is deleted. We scanned by quantitative multiplex polymerase chain reaction (PCR) of short fluorescent fragments (QMPSF) 200 kb of genomic sequences upstream of the MSH2 transcription initiation site in 21 HNPCC families with exon I deletions. This QMPSF scan revealed 12 distinct 5' breakpoints located up to 200 kb upstream of the MSH2 transcription initiation site. Sequencing analysis of the rearranged allele in 17 families revealed that most of the deletions (15/17) resulted from homologous Alu-mediated recombination. QMPSF and sequencing analysis in these 21 families led us to detect the presence of 20 distinct 5' breakpoints. In 14 out of 15 Alu-mediated recombinations, we found, either within the identical region in which the recombination had probably occurred or in its vicinity, the 26,bp Alu core sequence containing the recombinogenic Chi-like motif. Compared to the equivalent regions of other human genes, the MSH2 upstream region was found to contain a high density of Alu repeats (30% within 228 kb and 43% within 50 kb), most of which belong to the old Alu S subfamilies. In conclusion, this study demonstrates the heterogeneity of the breakpoints within the MSH2 upstream region and reveals the remarkable density of recombinogenic Alu sequences in this region.
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| 2. |
- Clendenning, M, et al.
(författare)
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Long-range PCR facilitates the identification of PMS2-specific mutations
- 2006
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794 .- 1098-1004. ; 27:5, s. 490-495
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Tidskriftsartikel (refereegranskat)abstract
- Mutations within the DNA mismatch repair gene, "postmeiotic segregation increased 2" (PMS2), have been associated with a predisposition to hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome). The presence of a large family of highly homologous PMS2 pseudogenes has made previous attempts to sequence PMS2 very difficult. Here, we describe a novel method that utilizes long-range PCR as a way to preferentially amplify PMS2 and not the pseudogenes. A second, exon-specific, amplification from diluted long-range products enables us to obtain a clean sequence that shows no evidence of pseudogene contamination. This method has been used to screen a cohort of patients whose tumors were negative for the PMS2 protein by immunohistochemistry and had not shown any mutations within the MLH1 gene. Sequencing of the PMS2 gene from 30 colorectal and I I endometrial cancer patients identified 10 novel sequence changes as well as 17 sequence changes that had previously been identified. In total, putative pathologic mutations were detected in 11 of the 41 families. Among these were five novel mutations, c.705+1G > T, c.736-741del6ins11, c.862_863del, c.1688G > T, and c.2007-IG > A. We conclude that PMS2 mutation detection in selected Lynch syndrome and Lynch syndrome-like patients is both feasible and desirable.
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| 3. |
- Staaf, Johan, et al.
(författare)
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Detection and precise mapping of germline rearrangements in BRCA1, BRCA2, MSH2, and MLH1 using zoom-in array comparative genomic hybridization (aCGH).
- 2008
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Ingår i: Human Mutation. - : Hindawi Limited. - 1059-7794. ; 29:4, s. 555-564
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Tidskriftsartikel (refereegranskat)abstract
- Disease-predisposing germline mutations in cancer susceptibility genes may consist of large genomic rearrangements that are challenging to detect and characterize using standard PCR-based mutation screening methods. Here, we describe a custom-made zoom-in microarray comparative genomic hybridization (CGH) platform of 60mer oligonucleotides. The 4 x 44 K array format provides high-resolution coverage (200-300 bp) of 400-700 kb genomic regions surrounding six cancer susceptibility genes. We evaluate its performance to accurately detect and precisely map earlier described or novel large germline deletions or duplications occurring in BRCA1 (n=11), BRCA2 (n=2), MSH2 (n=7), or MLH1 (n=9). Additionally, we demonstrate its applicability for uncovering complex somatic rearrangements, exemplified by zoom-in analysis of the PTEN and CDKN2A loci in breast cancer cells. The sizes of rearrangements ranged from several 100 kb, including large flanking regions, to <500-bp deletions, including parts of single exons that would be missed by standard multiplex ligation-dependent probe amplification (MLPA) methods. Zoom-in CGH arrays accurately defined the borders of rearrangements, allowing convenient design of primers for sequence determination of the breakpoints. The array platform can be streamlined for a particular application, e.g., focusing on breast cancer susceptibility genes, with increased capacity using multiformat design, and represents a valuable new tool and complement for genetic screening in clinical diagnostics.
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