Retinoic acid stimulates alpha-CAMKII gene expression in PC12 cells at a distinct transcription initiation site.
The promoter region of the alpha-subunit of the calcium/calmodulin-dependent protein kinase II (alpha-CaMKII) gene was inserted into a beta-galactosidase (beta-gal) reporter plasmid, and beta-gal activities were examined in neuroblastoma (NB2a) and pheochromocytoma (PC12) cells after transient or stable transfections. The alpha-CaMKII promoter was 12- to 45-fold more active in NB2a compared with PC12 cells after transient or stable transfections. All-trans retinoic acid (RA) stimulated reporter gene expression at both protein and mRNA levels in transfected PC12 cells. RA increased the level of endogenous alpha-CaMKII mRNA in untransfected PC12 cells by 4.4-fold. The transcription initiation site(s) (TIS) of the alpha-CaMKII gene in PC12 cells and rat brain was examined by RNase protection assays (RPA) and reverse transcriptase PCRs. The TIS for the alpha-CaMKII/beta-gal reporter gene in transfected PC12 cells was indistinguishable from the TIS+1 in rat hippocampus. In contrast, the only detectable TIS for the alpha-CaMKII gene in untransfected PC12 cells was located near the ATG translation start codon, 147 nucleotides 3' to TIS+1 in hippocampus. This unusual TIS was also the predominant TIS in rat cerebellum. These results suggest that the alpha-CaMKII promoter may contain sequences that respond directly or indirectly to RA. In addition, the unusual TIS of the alpha-CaMKII gene in PC12 cells and rat cerebellum may contribute to the very low expression of this gene compared with that in hippocampus.
Chen
J
J
Department of Neurobiology and Anatomy, University of Texas Medical School at Houston 77225, USA.
Kelly
P T
PT
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects*; D051379:Mice; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D009447:Neuroblastoma / Q000235:genetics / Q000473:pathology; D016716:PC12 Cells / Q000201:enzymology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014158:Transcription, Genetic / Q000187:drug effects*; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D015335:Molecular Probes; D012333:RNA, Messenger; D014212:Tretinoin; D017871:Calcium-Calmodulin-Dependent Protein Kinases