Construction of Flt3 internal tandem duplications and their expression in 32D cells.

(A) A human Flt3 fragment spanning nt1624 to 2134, containing either wild-type or 4 different ITD mutations, was substituted for the corresponding murine Flt3 sequences. The predicted amino acid sequence from either the wild-type or the 4 different ITDs is shown. Duplicated sequences are underlined. EC indicates extracellular domain; TM, transmembrane domain; JM, juxtamembrane domain; TK, tyrosine kinase domain; KI, kinase insert; hmWT, human/mouse wild-type; ITD, internal tandem duplication. (B) Expression of Flt3 receptors on the surface of 32D cells were analyzed by staining with PE-conjugated monoclonal rat antimouse Flt3 antibody. The shaded areas show staining with anti-Flt3; the blank areas show the isotype control.