Glutamine rich and basic region/leucine zipper (bZIP) domains stabilize cAMP-response element-binding protein (CREB) binding to chromatin.
We have examined the dynamics of cAMP-response element-binding protein (CREB) binding to chromatin in live cells using fluorescence recovery after photobleaching (FRAP). CREB was found to bind to target sites with a residence time of 100 s, and exposure to a cAMP agonist had no effect on these kinetics. In addition to the basic region/leucine zipper (bZIP) domain, a glutamine-rich trans-activation domain in CREB called Q2 also appeared to be critical for promoter occupancy. Indeed, mutations in Q2 that reduced residence time by FRAP assay disrupted target gene activation via CREB in cells exposed to a cAMP agonist. Notably, insertion of the glutamine-rich B trans-activation domain of SP1 into a mutant CREB polypeptide lacking Q2 stabilized CREB occupancy and rescued target gene activation. These results suggest a novel mechanism by which the family of glutamine-rich activators promotes cellular gene expression.
Mayr
Bernhard M
BM
Peptide Biology Laboratories, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Guzman
Ernesto
E
Montminy
Marc
M
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D005973:Glutamine / Q000737:chemistry; D006801:Humans; D047468:Immunoprecipitation; D007700:Kinetics; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D009154:Mutation; D016716:PC12 Cells; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry; D015533:Transcriptional Activation
D002843:Chromatin; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D010455:Peptides; D014157:Transcription Factors; D005973:Glutamine; D000242:Cyclic AMP