Abstract
The tumour suppressor p53 controls transcription of various genes involved in apoptosis, cell-cycle arrest, DNA repair and metabolism. However, its DNA-recognition specificity is not nearly sufficient to explain binding to specific locations in vivo. Here, we present evidence that KLF4 increases the DNA-binding affinity of p53 through the formation of a loosely arranged ternary complex on DNA. This effect depends on the distance between the response elements of KLF4 and p53. Using nuclear magnetic resonance and fluorescence techniques, we found that the amino-terminal domain of p53 interacts with the KLF4 zinc fingers and mapped the interaction site. The strength of this interaction was increased by phosphorylation of the p53 N-terminus, particularly on residues associated with regulation of cell-cycle arrest genes. Taken together, the cooperative binding of KLF4 and p53 to DNA exemplifies a regulatory mechanism that contributes to p53 target selectivity.
Highlights
The tumour suppressor p53 is at the centre of a large network responsible for the transcription of genes involved in apoptosis, senescence and cell-cycle arrest
Using analytical ultra-centrifugation (AUC) we found that full-length KLF4 was monomeric in solution and that the sample was homogenous and did not aggregate as judged by the presence of only one peak in the sedimentation coefficient distribution profile (Figure S1A and B)
Using AUC and fluorescence anisotropy titrations, we showed that the monomer of KLF4 binds DNA in a sequence-specific manner (Figure S1B and C, Tables S1 and S2)
Summary
The tumour suppressor p53 is at the centre of a large network responsible for the transcription of genes involved in apoptosis, senescence and cell-cycle arrest. Its function is to maintain genomic integrity upon stress. P53 controls the transcription of genes involved in a variety of cell survival processes such as DNA repair, metabolism regulation or embryo implantation [2,3]. Sequence specific recognition of DNA response elements is a key to correct functioning of p53 (reviewed in [4]). The p53 homologs p63 and p73 recognise the same response elements [8], but carry out functions distinct from p53 [9]. The situation is further complicated by the fact that the genome contains a very large number of putative p53/p63/p73 response elements [6], most of which are not necessarily involved in transcription regulation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
