Characterization of the Leptospira interrogans S10-spc-alpha operon

A ribosomal protein gene cluster from the spirochaete Leptospira interrogan s was characterized. This locus is homologous to the Escherichia coli S10, spc, and alpha operons. Analysis of L. interrogans RNA showed that the ribo somal protein genes within this cluster are cotranscribed, thus forming an operon. Two transcription initiation sites were mapped by primer extension, upstream of fus, the first gene in this cluster, and sequences from this r egion provided promoter activity in E. coli. Transcription terminates near a predicted stem-loop structure following rplQ, the last gene in the cluste r. These data suggest that two promoters upstream of fus direct transcripti on of this 17.5-kb ribosomal protein gene cluster. Comparison of the L. int errogans S10-spc-alpha cluster to homologous loci from Borrelia burgdorferi and Treponema pallidum provided evidence that this region of the genome un derwent several rearrangements during spirochaete evolution. (C) 2000 Publi shed by Elsevier Science B.V. All rights reserved.