title: Evolution of p53 transactivation specificity through the lens of a yeast-based functional assay.
abstract: Co-evolution of transcription factors (TFs) with their respective cis-regulatory network enhances functional diversity in the course of evolution. We present a new approach to investigate transactivation capacity of sequence-specific TFs in evolutionary studies. Saccharomyces cerevisiae was used as an in vivo test tube and p53 proteins derived from human and five commonly used animal models were chosen as proof of concept. p53 is a highly conserved master regulator of environmental stress responses. Previous reports indicated conserved p53 DNA binding specificity in vitro, even for evolutionary distant species. We used isogenic yeast strains where p53-dependent transactivation was measured towards chromosomally integrated p53 response elements (REs). Ten REs were chosen to sample a wide range of DNA binding affinity and transactivation capacity for human p53 and proteins were expressed at two levels using an inducible expression system. We showed that the assay is amenable to study thermo-sensitivity of frog p53, and that chimeric constructs containing an ectopic transactivation domain could be rapidly developed to enhance the activity of proteins, such as fruit fly p53, that are poorly effective in engaging the yeast transcriptional machinery. Changes in the profile of relative transactivation towards the ten REs were measured for each p53 protein and compared to the profile obtained with human p53. These results, which are largely independent from relative p53 protein levels, revealed widespread evolutionary divergence of p53 transactivation specificity, even between human and mouse p53. Fruit fly and human p53 exhibited the largest discrimination among REs while zebrafish p53 was the least selective.
authors: Laboratory of Transcriptional Networks, Centre for Integrative Biology (CIBIO), University of Trento, Mattarello, Trento, Italy.
authors: Mattia
authors: M
authors: Lion
authors: Laboratory of Transcriptional Networks, Centre for Integrative Biology (CIBIO), University of Trento, Mattarello, Trento, Italy.
authors: Ivan
authors: I
authors: Raimondi
authors: Laboratory of Transcriptional Networks, Centre for Integrative Biology (CIBIO), University of Trento, Mattarello, Trento, Italy.
authors: Stefano
authors: S
authors: Donati
authors: Laboratory of Microbial Genomics, Centre for Integrative Biology (CIBIO), University of Trento, Mattarello, Trento, Italy.
authors: Olivier
authors: O
authors: Jousson
authors: Laboratory of Transcriptional Networks, Centre for Integrative Biology (CIBIO), University of Trento, Mattarello, Trento, Italy.
authors: Yari
authors: Y
authors: Ciribilli
authors: Laboratory of Transcriptional Networks, Centre for Integrative Biology (CIBIO), University of Trento, Mattarello, Trento, Italy.
authors: Alberto
authors: A
authors: Inga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D004330:Drosophila; D019143:Evolution, Molecular; D006801:Humans; D007546:Isoquinolines; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D020218:Response Elements / Q000235:genetics*; D012441:Saccharomyces cerevisiae; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D015533:Transcriptional Activation / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D014982:Xenopus laevis; D015027:Zebrafish
chemical_list: D007546:Isoquinolines; D016159:Tumor Suppressor Protein p53; C017475:lucifer yellow