Panhandle polymerase chain reaction amplifies MLL genomic translocation breakpoint involving unknown partner gene.

Autor: Felix CA; Division of Oncology, Leonard and Madlyn Abramson Pediatric Research Center, Children's Hospital of Philadelphia, PA 19104-4318, USA., Kim CS, Megonigal MD, Slater DJ, Jones DH, Spinner NB, Stump T, Hosler MR, Nowell PC, Lange BJ, Rappaport EF
Jazyk: angličtina
Zdroj: Blood [Blood] 1997 Dec 15; Vol. 90 (12), pp. 4679-86.
Abstrakt: We used a new approach called panhandle polymerase chain reaction (PCR) to clone an MLL genomic translocation breakpoint in a case of acute lymphoblastic leukemia of infancy in which karyotype analysis was technically unsuccessful and did not show the translocation partner. Panhandle PCR amplified known MLL sequence 5' of the breakpoint and 3' sequence from the unknown partner gene from a DNA template with an intrastrand loop schematically shaped like a pan with a handle. The 7-kb panhandle PCR product contained the translocation breakpoint in MLL intron 8. The partner DNA included unique nonrepetitive sequences, Alu and mammalian apparent LTR-retrotransposon (MaLR) repetitive sequences, and a region of homology to expressed sequence tags. MaLR sequences have not been found before near leukemia-associated translocation breakpoints. The nonrepetitive sequences were not homologous to known partner genes of MLL. Screening of somatic cell hybrid and radiation hybrid lines by PCR and fluorescence in situ hybridization analysis of normal metaphase chromosomes mapped the partner DNA to chromosome band 4q21. Reverse transcriptase-PCR identified an MLL-AF-4 chimeric mRNA, indicating that panhandle PCR identified a fusion of MLL with a previously uncharacterized AF-4 intronic sequence. Panhandle PCR facilitates cloning translocation breakpoints and identifying unknown partner genes.
Databáze: MEDLINE