Schematic structure of TEL-JAK fusion proteins.

(A) Schematic of TEL and JAK2 proteins. The TEL oligomerization domain is represented by a hatched box. Arrows indicate the location of the fusion points characterized in human leukemias, as reported in work by Lacronique et al7 and Peeters et al.8 1,: T ALL; 2, atypical CML; 3, pre-B ALL; JH, JAK homology region. (B) TEL-JAK fusion proteins constructed by linking the 336 amino-terminal amino acids of human TEL to the tyrosine kinase domain of murine Jak2 (TEL-Jak2), murine Jak1 (TEL-Jak1), and human JAK3 (TEL-JAK3). Amino acids 53 to 154 of TEL are fused to the corresponding JH1 domains in mTEL-Jak2 and mTEL-TYK2 (human TYK2) constructs. The fusion points in the different chimera are indicated by an arrow. The human TEL-ABL fusion has been previously reported.9 Amino acids numbering on the JH1 part of TEL-JAK fusions refers to the sequences of the wild type JAKs.