title: Ca2+ channel alpha 1-subunit transcripts are differentially expressed in rat pheochromocytoma (PC12) cells following nerve growth factor treatment.
abstract: In this report, we describe the effect of nerve growth factor (NGF) on the transcriptional expression of voltage-dependent Ca2+ channel alpha 1 subunits, i.e., alpha 1A, alpha 1B, alpha 1C, alpha 1D, and alpha 1E in rat pheochromocytoma (PC12) cells. Using reverse transcriptase-coupled polymerase chain reaction (RT-PCR) and class-specific Ca2+ channel oligonucleotide probes, messenger RNA levels were measured and compared to Histone H3.3 transcript which remained relatively constant over the duration of NGF treatment. Although no statistically significant differences in P-type (alpha 1A) Ca2+ channel transcript levels were observed, N-type (alpha 1B) Ca2+ channel transcript levels increased 50% over control values (P values < 0.05) at days 7 and 14. In contrast, NGF treatment resulted in decreased levels of L-type (alpha 1C and alpha 1D) transcripts with alpha 1C decreasing steadily to approximately 50% of control (P value < 0.01) by 2 weeks, while alpha 1D decreased to approximately 20% of control (P value < 0.01) after 2 days treatment. No alpha 1E Ca2+ channel transcripts were detected in PC12 cells. For comparison, PC12 cells were also treated with another differentiative growth factor, i.e., basic fibroblast growth factor (bFGF) and a nondifferentiative growth factor epidermal growth factor (EGF). In contrast to NGF, bFGF and EGF treatment had no inhibitory effect on L-type (alpha 1C and alpha 1D) channel transcript levels after 3 days. Like NGF, EGF treatment had no statistically significant effect upon P-type (alpha 1A) transcript levels but increased in a biphasic manner following bFGF treatment. Presynaptic-associated alpha 1B (N-type) Ca2+ channel transcripts were observed decreased following EGF treatment (2 days) while L-type alpha 1C transcripts decreased after 7 days (P value < 0.01). Although a varied response to differentiative growth factors NGF and bFGF was observed, data presented here indicate that NGF treatment of PC12 cells results in 'late' increased expression of N-type Ca2+ channel transcripts, while L-type (alpha 1C and alpha 1D) Ca2+ channel transcripts appear to be down regulated.
authors.affiliation: Brain Research Laboratory of Biochemistry, University of Texas at San Antonio 78249, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Colston
authors.forename: J J
authors.initials: JJ
authors.lastname: Valdes
authors.forename: J P
authors.initials: JP
authors.lastname: Chambers
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000737:chemistry / Q000235:genetics*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000502:physiology*; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016716:PC12 Cells; D010446:Peptide Fragments / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015220:Calcium Channels; D009414:Nerve Growth Factors; D010446:Peptide Fragments; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2; D004815:Epidermal Growth Factor