FIG. 1.

Diagram of the pksN gene showing six exons (E1 to E6) and five introns (intervals between E1 to E6). Conserved positions of introns relative to the wA gene are indicated by asterisks. Conserved amino acids at catalytic sites are indicated by boxes whose sizes correspond to the aligned domains KS, AT, ACP, and thioesterase (TE). The solid line indicates the length of the C3-2 fragment used in transformation experiments. The 0.6-kb PCR fragment (dashed line) was used as a probe in Southern blot experiments. X, XbaI site (the first one is absent in the I₄ mutant).