title: [Biological microchip for establishing the structure of fusion transcripts involving MLL in children with acute leukemia].
abstract: MLL is involved in fusion genes with more than 100 partner genes, approximately 80 of which have been characterized at the molecular level. MLL fusion genes are often found in infants (60-80% of acute lymphoblastic leukemia (ALL) cases and 40-50% of acute myeloblastic leukemia (AML) cases) and are appreciably rarer (8-10%) in children older than 1 year of age. MLL rearrangements are important markers in diagnosis and treatment choice. To identify the partner gene is of primary importance for prognosis and minimal residual disease monitoring. The structure of the fusion gene, including localization of the MLL breakpoints, is also informative. A method was developed to examine the fusion transcripts in order to identify the partner gene among the six most common ones and to establish the exon structure of the rearranged MLL. The method includes a multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) to amplify and to fluorescently label a fusion transcript fragment and subsequent hybridization of the product on a biological microchip with immobilized oligonucleotides complementary to exons of MLL and its partner genes AFF1, MLLT1, MLLT3, MLLT4, MLLT10, and ELL. Hybridization results were verified by sequencing the RT-PCR products and, in some cases, performing long-distance inverse PCR (LDI-PCR). The study involved 38 bone marrow samples from ALL patients (including 33 children younger than 1 year of age) and 15 samples from AML patients (including 10 from children younger than 1 year of age). The main partner genes were AFF1 (49%), MLLT1 (27%), MLLT3 (12%), and MLLT10 (12%) in ALL and MLLT3 (80%), MLLT10 (10%), and MLLT4 (10%) in AML. Fusion gene transcripts most commonly included MLL exon 11 (58% of ALL cases and 50% of AML cases), suggesting a breakpoint in MLL intron 11.
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia.|Rogachev Federal Clinical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 119117 Russia.|nased@eimb.ru.
authors.forename: T V
authors.initials: TV
authors.lastname: Nasedkina
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia.
authors.forename: A Yu
authors.initials: AY
authors.lastname: Ikonnikova
authors.affiliation: Regional Children's Clinical Hospital no. 1, Yekaterinburg, 620149 Russia.|Institute of Medical Cell Technologies, Yekaterinburg, 620026 Russia.|Yeltsin Ural Federal University, Yekaterinburg, 620002 Russia.
authors.forename: G A
authors.initials: GA
authors.lastname: Tsaur
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Karateeva
authors.affiliation: Rogachev Federal Clinical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 119117 Russia.
authors.forename: Yu I
authors.initials: YI
authors.lastname: Ammour
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia.
authors.forename: M A
authors.initials: MA
authors.lastname: Avdonina
authors.affiliation: Rogachev Federal Clinical Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, 119117 Russia.
authors.forename: A I
authors.initials: AI
authors.lastname: Karachunskii
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia.
authors.forename: A S
authors.initials: AS
authors.lastname: Zasedatelev
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D020869:Gene Expression Profiling / Q000295:instrumentation* / Q000379:methods; D015973:Gene Expression Regulation, Leukemic; D011495:Histone-Lysine N-Methyltransferase / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051788:Myeloid-Lymphoid Leukemia Protein / Q000096:biosynthesis* / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation* / Q000379:methods; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis* / Q000235:genetics; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C497422:KMT2A protein, human; D015514:Oncogene Proteins, Fusion; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase
keywords: 11q23 chromosome rearrangements; MLL gene; acute leukemia; biological microchips; breakpoints; fusion transcript