Analysis of the promoters and transcripts involved in IS10 anti-sense RNA control.

Genetic analysis of eleven mutations affecting the IS10 promoters, pIN and pOUT, involved in anti-sense RNA control of transposase gene expression, and characterization of the transcripts, reveal that: (i) The transposase message (RNA-IN) and the anti-sense RNA (RNA-OUT) have been unambiguously identified in vivo. (ii) Five mutations affect pIN activity, and establish that pIN is the only IS10 promoter transcribing the tnp gene, and the only such IS10 promoter that responds to DNA-adenine methylation. (iii) Six mutations alter pOUT activity, and establish that pOUT is the only IS10 promoter specifying the anti-sense RNA-OUT. (iv) The latter, however, need not be so: heterologous promoters, if properly positioned, can also specify active anti-sense RNAs. (v) These heterologously promoted anti-sense RNAs are processed to species closely resembling native RNA-OUT.