This antibody reacts with a 52-56 kDa protein known as microphthalmia (Mi). This antibody reacts with both melanocytic and non-melanocytic isoforms of Mi. Mi is a basic helix-loop-helix-leucine zipper (b-HLH-ZIP) transcription factor implicated in pigmentation, mast cells and bone development. There are two known isoforms of Mi differing by 66 amino acids at the amino terminus.
