Identification of candidate genes on chromosome band 20q12 by physical mapping of translocation breakpoints found in myeloid leukemia cell lines

Donal MacGrogan, Sara Alvarez, Tony DeBlasio, Suresh C. Jhanwar, Stephen D. Nimer

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

Deletions of the long arm of chromosome 20 have been reported in a wide range of myeloid disorders, and may reflect loss of critical tumor suppressor gene(s). To identify such candidate genes, 65 human myeloid cell line DNAs were screened by polymerase chain reaction (PCR) for evidence of allelic loss at 39 highly polymorphic loci on the long arm of chromosome 20. A mono-allelic pattern was present in eight cell lines at multiple adjacent loci spanning the common deleted regions (CDRs) previously defined in primary hematological samples, suggesting loss of heterozygosity (LOH) at 20q. Fluorescence in situ hybridization (FISH) was then performed using a series of yeast artificial chromosomes (YACs) ordered in the CDR, and in five of eight cell lines, the deletions resulted from cytogenetically detectable whole chromosomal loss or large interstitial deletion, whereas in another cell line deletion was associated with an unbalanced translocation. LOH in the CMK megakaryocytic cell line, which has a hypotetraploid karyotype, was associated with a der(20)t(1;20)(q32;q12)x2 leading to complete deletion of the CDR. Three additional unbalanced translocations were found within the CDR and all three breakpoints mapped to a single YAC. We then used a series of P1 artificial chromosomes (PACs) spanning this YAC clone, and two PACs produced 'split' signals suggesting that they each span one of these breakpoints. Exon trapping using PACs that overlap the breakpoint regions yielded portions of six genes and evaluation of these genes as candidate tumor suppressor genes is underway. The limited information available about these genes suggests that the h-l(3)mbt gene is the most attractive candidate.

Original languageEnglish (US)
Pages (from-to)4150-4160
Number of pages11
JournalOncogene
Volume20
Issue number31
DOIs
StatePublished - Jul 12 2001
Externally publishedYes

Keywords

  • 20q deletion
  • Loss of heterozygosity
  • Myeloid leukemia

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research
  • Genetics

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