title: Distinct cytoplasmic and nuclear functions of the stress induced protein DDIT3/CHOP/GADD153.
abstract: DDIT3, also known as GADD153 or CHOP, encodes a basic leucine zipper transcription factor of the dimer forming C/EBP family. DDIT3 is known as a key regulator of cellular stress response, but its target genes and functions are not well characterized. Here, we applied a genome wide microarray based expression analysis to identify DDIT3 target genes and functions. By analyzing cells carrying tamoxifen inducible DDIT3 expression constructs we show distinct gene expression profiles for cells with cytoplasmic and nuclear localized DDIT3. Of 175 target genes identified only 3 were regulated by DDIT3 in both cellular localizations. More than two thirds of the genes were downregulated, supporting a role for DDIT3 as a dominant negative factor that could act by either cytoplasmic or nuclear sequestration of dimer forming transcription factor partners. Functional annotation of target genes showed cell migration, proliferation and apoptosis/survival as the most affected categories. Cytoplasmic DDIT3 affected more migration associated genes, while nuclear DDIT3 regulated more cell cycle controlling genes. Cell culture experiments confirmed that cytoplasmic DDIT3 inhibited migration, while nuclear DDIT3 caused a G1 cell cycle arrest. Promoters of target genes showed no common sequence motifs, reflecting that DDIT3 forms heterodimers with several alternative transcription factors that bind to different motifs. We conclude that expression of cytoplasmic DDIT3 regulated 94 genes. Nuclear translocation of DDIT3 regulated 81 additional genes linked to functions already affected by cytoplasmic DDIT3. Characterization of DDIT3 regulated functions helps understanding its role in stress response and involvement in cancer and degenerative disorders.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Jauhiainen
authors.forename: Christer
authors.initials: C
authors.lastname: Thomsen
authors.forename: Linda
authors.initials: L
authors.lastname: Strömbom
authors.forename: Pernilla
authors.initials: P
authors.lastname: Grundevik
authors.forename: Carola
authors.initials: C
authors.lastname: Andersson
authors.forename: Anna
authors.initials: A
authors.lastname: Danielsson
authors.forename: Mattias K
authors.initials: MK
authors.lastname: Andersson
authors.forename: Olle
authors.initials: O
authors.lastname: Nerman
authors.forename: Linda
authors.initials: L
authors.lastname: Rörkvist
authors.forename: Anders
authors.initials: A
authors.lastname: Ståhlberg
authors.forename: Pierre
authors.initials: P
authors.lastname: Åman
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002448:Cell Adhesion; D002453:Cell Cycle; D002465:Cell Movement; D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005354:Fibrosarcoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008080:Liposarcoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013629:Tamoxifen / Q000494:pharmacology; D051742:Transcription Factor CHOP / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; C497249:DDIT3 protein, human; D012333:RNA, Messenger; D011994:Recombinant Proteins; C485184:enhanced green fluorescent protein; D013629:Tamoxifen; D051742:Transcription Factor CHOP; D049452:Green Fluorescent Proteins