ASH1L [SEP] chromosome
Hox gene expression and body segment identity. Drosophila Ash1 interacts with trithorax to regulate ultrabithorax expression.
The human ASH1L gene spans 227.5 kb on chromosome 1, band q22. This region is rearranged in a variety of human cancers such as leukemia, non-Hodgkin’s lymphoma, and some solid tumors. The gene is expressed in multiple tissues, with highest levels in brain, kidney, and heart, as a 10.5-kb mRNA transcript.
Structure.
Human ASH1L protein is 2969 amino acids long with a molecular weight of
both MLL1 and ASH1L for activation, whereas MLL1 or ASH1L alone are not sufficient to activate transcription. The methyltransferase activity of ASH1L is not required for Hox gene activation but instead has repressive action. Knockdown of ASH1L in K562 cells causes up-regulation of the ε-globin gene and down-regulation of myelomonocytic markers GPIIb and GPIIIa, and knockdown of ASH1L in lineage marker-negative hematopoietic progenitor cells skews differentiation from myelomonocytic towards lymphoid or erythroid lineages. These results imply that ASH1L, like MLL1, facilitates myelomonocytic differentiation of hematopoietic