Two signals mediate hormone-dependent nuclear localization of the glucocorticoid receptor.
We have detected nuclear localization signals within the 795 amino acid rat glucocorticoid receptor. Using a transient expression assay, we monitored by immunofluorescence the subcellular distribution of receptor derivatives and beta-galactosidase-receptor fusion proteins. Two distinct nuclear localization signals, NL1 and NL2, were defined. NL1 maps to a 28 amino acid segment closely associated, but not coincident with the DNA binding domain; NL2 resides within a 256 amino acid region that also includes the hormone binding domain. Most importantly, nuclear localization of fusion proteins containing either the full-length receptor or the NL2 region alone is fully hormone-dependent; similar results were obtained with the wild-type receptor, provided the analysis was performed in medium lacking serum and phenol red. The rate of hormone-induced nuclear localization of an NL2-containing fusion protein is consistent with the rapid kinetics of hormone-regulated transcription mediated by the receptor. Thus, hormonal control of nuclear localization contributes to the modulation of glucocorticoid receptor transcriptional regulatory activity.
D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002872:Chromosome Deletion; D005455:Fluorescent Antibody Technique; D005796:Genes; D005822:Genetic Vectors; D009154:Mutation; D021382:Protein Sorting Signals / Q000378:metabolism*; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000032:analysis / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics
D021382:Protein Sorting Signals; D011965:Receptors, Glucocorticoid; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase