[Variant fusion transcript in ALL children with E2A-PBX1 fusion gene positive].

ABSTRACT

The study was aimed to investigate the expression of E2A-PBX1 fusion gene in children with acute lymphoblastic leukemia (ALL). The primers located at different sites of E2A and PBX1 gene were used to screen for the fusion gene in 410 children with ALL, including 362 cases of B cell ALL and 48 cases of T cell ALL. The results showed that 17 children carried the fusion gene. The positive rate was 4.1%. Furthermore, all the positive cases expressed a variant type of fusion transcript. It resulted from different splicing of the 13th exon (159 bp) of E2A gene. Analyses with BLASTn indicated that the variant type of transcript retained the open reading frame. However, the loss of 53 amino acid residues which were located at the 2nd activation domain resulted in the partial deletion of the putative loop-helix (LH) structure as well as the complete deletion of the heptad leucine repeat. It is concluded that all the children with ALL positive for the E2A-PBX1 fusion gene express typical and variant fusion transcripts. The latter resulted from different splicing of the 13th exon (159 bp) of E2A gene. The loss of 53aa would lead to the partial deletion of the putative loop-helix (LH) structure as well as the complete deletion of the heptad leucine repeat.