FIG. 1.

Primer extension analysis of mRNA start sites in the PM2 genome. The numbers refer to the nucleotide coordinates of the PM2 genome (AF155037). (A) PM2 genome map linearized at a unique EcoRII site. The genes (assigned by Roman numerals) and ORFs (marked with lowercase letters) (28, 33) are presented with arrows indicating the direction of transcription. Positions of the predicted hairpin structures are indicated by an open circle upon the scale bar (33). The genes confirmed to code for structural proteins are shaded gray. The mRNA start sites determined by primer extension are marked with downward arrows at the top of the figure. (B) Results of the primer extension reactions (lane E) analyzed parallel to the sequencing reactions in a sequencing gel.