title: Cis-regulatory elements are harbored in Intron5 of the RUNX1 gene.
abstract: BACKGROUND
  Human RUNX1 gene is one of the most frequent target for chromosomal translocations associated with acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). The highest prevalence in AML is noted with (8; 21) translocation; which represents 12 to 15% of all AML cases. Interestingly, all the breakpoints mapped to date in t(8;21) are clustered in intron 5 of the RUNX1 gene and intron 1 of the ETO gene. No homologous sequences have been found at the recombination regions; but DNase I hypersensitive sites (DHS) have been mapped to the areas of the genes involved in t(8;21). Presence of DHS sites is commonly associated with regulatory elements such as promoters, enhancers and silencers, among others.
  
  
  RESULTS
  In this study we used a combination of comparative genomics, cloning and transfection assays to evaluate potential regulatory elements located in intron 5 of the RUNX1 gene. Our genomic analysis identified nine conserved non-coding sequences that are evolutionarily conserved among rat, mouse and human. We cloned two of these regions in pGL-3 Promoter plasmid in order to analyze their transcriptional regulatory activity. Our results demonstrate that the identified regions can indeed regulate transcription of a reporter gene in a distance and position independent manner; moreover, their transcriptional effect is cell type specific.
  
  
  CONCLUSIONS
  We have identified nine conserved non coding sequence that are harbored in intron 5 of the RUNX1 gene. We have also demonstrated that two of these regions can regulate transcriptional activity in vitro. Taken together our results suggest that intron 5 of the RUNX1 gene contains multiple potential cis-regulatory elements.
authors.forename: Boris
authors.initials: B
authors.lastname: Rebolledo-Jaramillo
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Alarcon
authors.forename: Valentina I
authors.initials: VI
authors.lastname: Fernandez
authors.affiliation: Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Concepcion, Chile. sgutierr@udec.cl.
authors.forename: Soraya E
authors.initials: SE
authors.lastname: Gutierrez
mesh_terms: D000818:Animals; D002891:Chromosomes, Human, Pair 21; D002898:Chromosomes, Human, Pair 8; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics* / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000737:chemistry / Q000378:metabolism; D018922:HL-60 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D007438:Introns; D019169:Jurkat Cells; D051379:Mice; D011401:Promoter Regions, Genetic; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D014178:Translocation, Genetic
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D003850:Deoxyribonuclease I