title: Novel loss-of-function mutations of the haematopoiesis-related transcription factor, acute myeloid leukaemia 1/runt-related transcription factor 1, detected in acute myeloblastic leukaemia and myelodysplastic syndrome.
abstract: AML1/RUNX1, which encodes a transcription factor essential for definitive haematopoiesis, is a frequent target of leukaemia-associated chromosome translocations. Point mutations of this gene have also recently been associated with leukaemia and myelodysplastic syndrome (MDS). To further define the frequency and biological characteristics of AML1 mutations, we have examined 170 cases of such diseases. Mutations within the runt-domain were identified in five cases: one of de novo acute myeloid leukaemia (AML) and four of MDS. Where multiple time point samples were available, mutations were detected in the earliest samples, which persisted throughout the disease course. Of the five mutations, one was a silent mutation, two were apparent loss-of-function mutations caused by N-terminal truncation, and two were insertions, I150ins and K168ins, which preserved most of the AML1 DNA-binding domain. Both AML1 molecules with insertion mutations were non-functional in that they were unable to rescue haematological defects in AML1-deficient mouse embryonic stem cells. In addition, activating mutations of N-ras, deletion of chromosome 12p, or inactivation of TP53 accompanied some of the AML1 mutations. Together, these observations strongly suggest that one-allele inactivation of AML1 serves as an initial or early event that plays an important role in the eventual development of overt diseases with additional genetic alterations.
authors.affiliation: Molecular-Targeting Cancer Prevention, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramach-Hirokoji, Kamigyo-ku, Kyoto, Japan.
authors.forename: Mitsushige
authors.initials: M
authors.lastname: Nakao
authors.forename: Shigeo
authors.initials: S
authors.lastname: Horiike
authors.forename: Yoko
authors.initials: Y
authors.lastname: Fukushima-Nakase
authors.forename: Motohiro
authors.initials: M
authors.lastname: Nishimura
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Fujita
authors.forename: Masafumi
authors.initials: M
authors.lastname: Taniwaki
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Okuda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D020868:Gene Silencing; D005818:Genetic Engineering; D006410:Hematopoiesis / Q000235:genetics*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D008297:Male; D051379:Mice; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics; D017354:Point Mutation; D018807:Polymorphism, Single-Stranded Conformational; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D013234:Stem Cells / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; C493728:RUNX1 protein, human; C493726:Runx1 protein, mouse; D014157:Transcription Factors