| A yeast two hybrid screen of a Jurkat ( T cell ) derived cDNA library , using SATB 1 ( a matrix attachment region binding protein ) as the bait , yielded four independent isolates of a novel variant of the DNA directed RNA polymerase 2 , subunit 11 ( RPB 11 ) . ^^^ The exclusive association of SATB 1 with one form of RPB 11 is influenced primarily by the N terminal amino acid disparity , as deletion of the entire C terminus does not alter interaction affinity . ^^^ Association of RPB 11 with SATB 1 maps between amino acids 58 and 222 of SATB 1 , a region that includes a PDZ like dimerization motif . . ^^^ |