Macromolecular requirements for the physical initiation of cell division in a filamentous mutant of Agmenellum quadruplicatum

Abstract

Strain SN29 is a low temperature-sensitive cell division mutant impaired in the initiation of cross-wall formation. This mutant can be stimulated to initiate multiple divisions by the addition of ethanol. Ethanol-stimulated division and subsequent cell separation are insensitive to inhibition of DNA synthesis but are sensitive to inhibition of protein and RNA synthesis for the first hour. However, prior inhibition of RNA synthesis or protein synthesis does not block the initiation of cross-walls as assessed by light and electron microscopy. These results indicate that the newly synthesized RNA and protein are not needed for the initiation of cross-wall formation and must function in some subsequent step of the division process and that ethanol may act directly to stimulate cross-wall formation, possibly by interacting with the cell membrane.