PATZ1 and mastocytoma: Overexpression of a putative dominant-negative version of MAZR consisting of aa 409–496 of the zinc-finger domain in MST mastocytoma cells led to reduced expression levels Tpsb2 (encoding for Tryptase beta 2, also known as Mast cell protease 6), while overexpression of MAZR together with MITF in Jurkat T cells enhanced Tpsb2 promoter activity [12].