| We show here that ( 1 ) 5 Jun mediated repression of the endogenous SPARC gene is enhanced by Fra 2 but alleviated by ATF 2 , Fra 2 and ATF 2 being the two major partners of 5 Jun in the transformed cells ; ( 2 ) high basal activity as well as repression by 5 Jun and modulation by Fra 2 and ATF 2 is restricted to a small proximal fragment ( 124 / +16 ) of the chicken SPARC promoter ; ( 3 ) the activity of this minimal promoter is modulated by all the AP 1 family members known in chickens ( c Jun and JunD ; c Fos and Fra 2 ; ATF 2 ; c Maf , MafA , and MafB ) . ^^^ |