The entire coding region of mouse Asxl1 cDNA with a TAC to TGA change resulting in a stop codon mutation on the Y588 site with a FLAG tag is under the control of the Vav1 promoter. Y558X in the mouse corresponds to human Y591X which is the most frequent nonsense mutation type in patients with malignant myeloid diseases. Western blot analysis confirmed the expression of a truncated protein. Five lines were generated, I through V. The pound symbol (#) is used when no line is specified and/or lines are pooled. J:257690 reports pooled data from lines I and II.