Spontaneous mutation results in loss of the cytadhesin (P1) of Mycoplasma pneumoniae

The cytadhesin (P1) structural gene of a spontaneous mutant of Mycoplasma pneumoniae which displayed a P1-negative phenotype was analyzed. An extra adenine was discovered in a stretch of normally seven adenines near the N-terminal region of the mutant P1 structural gene. The frameshift mutation resulted in the early termination of protein translation. Possible causes of the mutation are discussed.