Mediator Complex Subunit 22 (MED22)

MED22 is located in the surfeit gene cluster, a group of very tightly linked housekeeping genes that do not share sequence similarity. The gene is oriented in a head-to-head fashion with RPL7A (SURF3) and the two genes share a bidirectional promoter. The encoded proteins are localized to the cytoplasm. Two alternative transcript variants encoding different isoforms have been identified for this gene.The longest cDNA, SURF5a, encodes a deduced 140-amino acid protein with a calculated molecular mass of 16.7 kD. SURF5b encodes a deduced 200-amino acid protein with a calculated molecular mass of 21 kD. The first 137 amino acids of both proteins are identical. A 1.4-kb SURF5b transcript was detected only in heart, brain, skeletal muscle, and pancreas, and in human teratocarcinoma cells.