Fig. 7. Secondary sense and antisense RNAs in transgene-induced gene silencing. Low-molecular weight RNAs were isolated from the wild-type strain (wt), an albino transformant containing a full-length carB transgene (a3; plasmid pMAT647) and an albino transformant containing 3′-truncated carB exogenous sequences (a5; plasmid pMAT650). Cultures were grown for 24 h in liquid medium under continuous illumination conditions. Fifteen micrograms of RNA was loaded in each lane. (A) RNA blot hybridized with a carB antisense-specific riboprobe (Figure 1A, probe a′). (B) Identical RNA blot hybridized with the carB sense-specific riboprobe (Figure 1A, probe a). (C) RNA blot hybridized with the 5′-end carB antisense-specific riboprobe (Figure 1A, probe b′). (D) Identical blot hybridized with the 3′-end carB antisense-specific riboprobe (Figure 1A, probe c′). Ten picomoles per lane of 29-mer (A and B), 25-mer (C) or 30-mer (D) DNA oligonucleotides in antisense orientation (AS) and 25-mer DNA oligonucleotides in sense orientation (S) were used as size markers.