We previously identifeied a movable and regulable inactivation function within the central region (CRts247) of a temperature-sensitive p53(p53ts)mutant, p53N247I. Here we showed that central regions from several p53ts mutants behaved similarly, i.e. they repressed a neighboring activation domain only when existing in the mutant status. Using chimeric protein GAL4VP16-CRts247 as an example, we demonstrated thet de novo protein synthesis was not required for the reactivation of the chimeric protein, indicating that a post-transcriptional mechanism was involved in the control of CRts247 activity. The CRts247-conferred thermo-regulability did not work via a mechanism demanding either an alteration of the subcellular compartmentalization of or the inactivationof DNA-binding activity of the GAL4 chimera.Futher, CRts247 did not function in trans, eliminating the possibillity that the observed repression was because of the competition for a putative factor(s) by the mutant p53 domain. Rather, CRts247 bestowed temperature-dependent interaction with hTAFII32 to the VP16 activation domain. In a parallel experiment, CRts247 also caused a large reduction in the affinity of hTAFII32 to the p53 activation domain at the nonpermissive temperature. These results strongly suggested that inhibition of hTAF II32 binding could be one of the mechanisms responsible for the transcriptional represson by mutant p53 central regions.
關聯:
JOURNAL OF BIOLOGICAL CHEMISTRY 274(12 )7748 ~7755
