pCMV-rAct structure and activin expression. (A) Diagram of the pCMV-rAct construct. Functional elements include the cytomegalovirus (CMV) promoter, the activin cDNA, and the human growth hormone (hGH) poly(A) signal. (B) RT-PCR and (C) Southern blot analysis were performed as described in methods. Marker of pGEM3Z/infI was loaded in lane 1. RNA from the pCMV-rAct-injected mice was loaded in lane 3 after treatment with DNase I, reverse transcriptase, and PCR. RNAs from control mice and from the pCMV-rAct-injected mice without reverse transcription were used as a normal (lane 2) and an internal control (lane 4), respectively. pCMV-rAct plasmid was used as a positive control (lane 5). RT: reverse transcription, pCMV-rAct: pCMV-rAct-injected mice. +: treated (or reacted), -: not treated (or not reacted).