Fig. 1.

(A) Representative agarose gel electrophoresis showing a competitive reverse transcriptase-polymerase chain reaction (RT-PCR) for GSK-3β messenger RNA (mRNA) in dorsolateral prefrontal cortex (DLPFC) of one normal control (NC) subject. Decreasing concentrations of internal standard (IS) for GSK-3β (100–6.25 pg) were added to a constant amount (0.5 μg) of total RNA. The mixtures were reverse transcribed and polymerase chain reaction amplified in the presence of trace amounts of ³²P-dCTP (cytidine triphosphate); aliquots were digested by XhoI and electrophoresed on 1.5% agarose gel. The higher molecular size band corresponds to the amplification product arising from the target RNA, whereas the lower band arises from the IS RNA for GSK-3β after it is digested with XhoI. (B) Standard curve is plotted for each sample as the counts incorporated into the IS divided by the counts incorporated into the target mRNA versus the known amount of IS added. The amount of target molecule was calculated using the formula, y = mx + b, where x represents the concentration of the target when y = 1 (a molar ratio of 1:1). Results are expressed as attomoles target gene/μg of total RNA.