sxy-1, a Haemophilus influenzae mutation causing greatly enhanced spontaneous competence.

AUTOR(ES)

Redfield, R J

RESUMO

A Haemophilus influenzae strain carrying a competence-enhancing mutation (sxy-1) was selected by transformation of a mutagenized culture in exponential growth at low cell density, where spontaneous competence is very rare. Under these conditions, sxy-1 cells spontaneously transformed 100 to 1,000 times more efficiently than wild-type cells. Moreover, sxy-1 cells responded to all known competence-inducing treatments with further increases in transformation frequency. At high cell densities, sxy-1 cells spontaneously developed the level of competence reached by wild-type cells only after maximal induction by transfer to starvation medium. The sxy-1 mutation appears to act early in the sequence of events leading to competence; it increased the competence of cells carrying the early-acting transformation-defective (Tfo-) mutation tfo-98 by as large a factor as it did the competence of wild-type cells, but it had no effect when combined with another early-acting Tfo- mutation (tfo-87) or with the late-acting Tfo- mutation rec-2.

Documentos Relacionados

• The Haemophilus influenzae sxy-1 mutation is in a newly identified gene essential for competence.
• The Haemophilus influenzae adenylate cyclase gene: cloning, sequence, and essential role in competence.
• Generation and release of DNA-binding vesicles by Haemophilus influenzae during induction and loss of competence.
• The Haemophilus influenzae dprABC genes constitute a competence-inducible operon that requires the product of the tfoX (sxy) gene for transcriptional activation.
• Development of Competence of Haemophilus influenzae