ctr1, a gene involved in a signal transduction pathway of the gliding motility in the cyanobacterium Synechocystis sp PCC 6803

We generated random Tn5 mutations in Synechocystis sp, PCC 6803 in search f or genus involved in the signal transduction cascade for the cyanobacterial gliding motility. One of the non-gliding Tn5 mutants, S1-105, had an inser tional inactivation in the slr1044 gene encoding a putative methyl-acceptin g chemotaxis protein. Interposon mutation on the slr1044 (named ctr1) in th e bacterium also eliminated gliding motility. In the interposon mutant, the expression of pilA1 was 5-fold decreased compared with that of wild-type a nd thick pill, that are believed to he the motor for gliding, could not he observed by an electron microscope. Therefore, we suggest that the Ctr1 pro tein functions as a transducer that regulates the expression of pilA1, and thus is required for the biogenesis of thick pili. (C) 2001 Federation of E uropean Biochemical Societies. Published by Elsevier Science B,V. All right s reserved.