Runx-1: A protein that is a transcription factor controlling when genes are switched on or off. Runx-1 acts by binding to regulatory sequences -- specific sequences of DNA close to the genes they regulate. These DNA sequences, called Runx-1 binding sites, are scattered throughout the human genome, wherever there is a gene under the control of Runx-1. Runx-1 stands for runt-related transcription factor 1.
A change in Runx-1 appears to cause a type of leukemia. The gene for Runx-1 is rearranged in acute myeloid leukemia (AML), especially the M2 subtype of AML. (The Runx-1 gene is often called AML1.) A translocation between chromosomes 22 and 8 juxtaposes AML1 with an unfamiliar gene, usually EAP or MDS1, to create a fusion gene.
Changes in Runx-1 also appear to contribute to autoimmune diseases. A Runx-1 binding site on chromosome 2 is altered in many patients with systemic lupus erythematosus. Many psoriasis patients have a changed Runx-1 binding site on chromosome 17. And a Runx-1 binding site on chromosome 17 is changed in patients with rheumatoid arthritis. Thus, there are genetic connections, some involving Runx-1, between diverse autoimmune diseases.