Long AT-rich palindromes and the constitutional t(11;22) breakpoint

Hiroki Kurahashi, Beverly S. Emanuel

研究成果: Article査読

121 被引用数 (Scopus)

抄録

The constitutional t(11;22) is the most frequently occurring non-Robertsonian translocation in humans. The breakpoint (BP) of the t(11;22) has been identified within palindromic AT-rich repeats (PATRRs) on chromosomes 11 and 22, suggesting that hairpin/cruciform structures mediate double-strand breaks leading to the translocation. To further characterize the mechanism of the translocation, identification of the precise location of the translocation BP is essential. Thus, the PATRRs from normal chromosomes 11 have been analyzed in detail. The majority of individuals have a PATRR that is 445 bp in length with a nearly symmetrical structure. The shorter, previously reported 204 bp PATRR has been shown to be a rare polymorphism. There are several nucleotide differences between the proximal and distal arms of the 445 bp palindrome (cis-morphisms) that correspond to five polymorphic sites within the PATRR. Using these data, the junction fragments of 40 unrelated t(11;22) families have been examined to determine the position of their 11q23 BPs. Sequence analysis demonstrates that BPs are located at the center of the longer PATRR in 39 of 40 cases. The data suggest that the center of the palindrome is susceptible to double-strand breaks leading to translocations that sustain small symmetrical deletions at the BP junction. The sequence of the larger, chromosome 22 PATRR deduced from junction fragments has three cis-morphisms, and the derivative chromosomes sustain symmetric deletions at the center of 22q11 PATRR. In one unusual case, the BPs on both chromosomes appear to correspond to these cis-morphic sites, suggesting that double-strand breaks at mismatched regions caused this variant translocation. De novo t(11;22) BPs have been analyzed using translocations detected in sperm samples from normal males. cis-Morphisms reveal no exclusive utilization of a particular allele in meiosis to produce the translocation. Our data lend support to the hypothesis that palindrome-mediated double-strand breaks in meiosis cause illegitimate recombination between 11q23 and 22q11 resulting in this recurrent translocation.

本文言語English
ページ(範囲)2605-2617
ページ数13
ジャーナルHuman molecular genetics
10
23
DOI
出版ステータスPublished - 01-11-2001
外部発表はい

All Science Journal Classification (ASJC) codes

  • 分子生物学
  • 遺伝学
  • 遺伝学(臨床)

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