Characterization of Solt, a novel SoxLZ/Sox6 binding protein expressed in adult mouse testis

SoxLZ/Sox6, a member of the Sox protein family, contains a leucine zipper m otif in addition to an HMG box, which is its DNA binding domain. Here we ha ve identified a novel SoxLZ/Sox6 binding protein, termed Solt, which we obt ained independently using both a far-Western blot and a yeast two-hybrid sc reen, Like SoxLZ/Sox6 mRNA, Solt mRNA was exclusively expressed in the test is in mouse. Solt contains an unusual leucine zipper, which bound to the le ucine zipper region of SoxLZ/Sox6 in vitro. In transient transfection assay s in CHO cells with SoxLZ/Sox6 containing the transactivational region of h erpes simplex virus VP16, expression of a reporter gene that carries a cis binding region for Sox proteins was significantly enhanced by the co-expres sion of Solt and Ca2+/calmodulin-dependent protein kinase IV. (C) 2000 Fede ration of European Biochemical Societies. Published by Elsevier Science B.V . All rights reserved.