Fig 3. Transgene hairpin silencing is defective in qip null mutant.

(A) Phenotype of the descendants of white colonies obtained from transformation of wild type (R7B, right) and the qipΔ mutant (left) with plasmid pMAT1253, which expresses a carB mRNA hairpin. The color of the colonies was analyzed after 48 hours growth on YNB media in the light. (B) sRNA enriched samples (50 μg) from 11 non-silenced transformants in the qipΔ background carrying pMAT1253 were obtained after 48 hour incubation in liquid YNB media pH = 4.5. A carB probe that specifically detects antisense RNA was used for hybridization in a northern blot assay. A silenced transformant with the same plasmid but in a WT background was used as a positive control. Ribo 3 (antisense, AS) and carB25 (sense, S) primers were used as size and sense markers (see Methods). tRNA were stained with ethidium bromide and served as a loading control.