Figure 7.

Effects of TIS11b knockdown on StAR mRNA expression in BAC, MA-10, and Y-1 cells. A, BAC were transfected with TIS11b siRNA or scrambled siRNA. After 48 h, cells were either lysed to evaluate TIS11b suppression or incubated with fresh medium containing 10 nm ACTH for the indicated period of time. At each time of stimulation by ACTH, total RNA was isolated, and RT-PCR analysis was performed to determine total StAR mRNA expression levels. HPRT mRNA levels were used for standardization. Inset shows effects on TIS11b mRNA. B, Primer pairs used for selective RT-PCR quantification of Star short (primer pair 2) and long transcripts (primer pair1) after reverse transcription using poly-dT primers. C, Br-cAMP stimulation of Star transcript levels in MA-10 cells treated with either nontarget siRNA or TIS11b siRNA for 48 h. Primer pairs 1 and 2 are compared with β-actin mRNA for standardization to measure 3.5- and 1.6-kb transcripts. D, Equivalent analyses for Y-1 cells. Data represent mean ± sd for triplicate cultures.