Cell-shape-dependent modulation of p52(PAI-1) gene expression involves a secondary response pathway.
Expression of the rat p52(PAI-1) gene is positively regulated by agents that influence cellular microfilament organization and/or cell-to-substrate adhesion [e.g. cytochalasin D (CD) and sodium n-butyrate (NaB)] [Higgins, Chaudhari and Ryan (1991) Biochem. J. 273, 651-658; Higgins, Ryan and Providence (1994) J. Cell. Physiol. 159, 187-195]. As shape-responsive genes may be subject to inducer-specific controls, the biochemical mechanisms underlying the shape-dependent pathway of p52(PAI-1) gene regulation were examined in v-ras-transformed rat kidney (KNRK) cells. NaB and/or CD effectively stimulated p52(PAI-1) run-off transcription and augmented de novo p52(PAI-1) mRNA and protein synthesis in KNRK cells; induction at both the mRNA and protein levels was inhibited by actinomycin D. Pretreatment with cycloheximide (CX) markedly attenuated NaB- and/or CD-stimulated p52(PAI-1) expression. CX alone, however, induced low levels of p52(PAI-1) mRNA; increased p52(PAI-1) protein synthesis was evident after release of KNRK cells from CX blockade. Such CX-mediated induction was also sensitive to actinomycin D. Full stimulation of p52(PAI-1) expression in KNRK cells in response to the shape modulators NaB and/or CD involves transcriptional activation of the p52(PAI-1) gene, requires de novo RNA synthesis and occurs through a secondary-response (i.e. protein-synthesis-dependent) pathway.
Higgins
P J
PJ
Department of Microbiology, Immunology and Molecular Genetics, Albany Medical College, NY 12208.
Staiano-Coico
L
L
Ryan
M P
MP
D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002460:Cell Line; D002461:Cell Line, Transformed; D048429:Cell Size / Q000187:drug effects / Q000235:genetics*; D003513:Cycloheximide / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000187:drug effects; D011905:Genes, ras; D007668:Kidney; D007700:Kinetics; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis
D002087:Butyrates; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D020148:Butyric Acid; D003609:Dactinomycin; D015638:Cytochalasin D; D003513:Cycloheximide