Isolation and characterization of specialized transducing λ phages carrying ribosomal protein genes of Escherichia coli

✍ Scribed by Kitakawa, Madoka ;Blumenthal, Laura ;Isono, Katsumi

• Publisher: Springer
• Year: 1980
• Tongue: English
• Weight: 596 KB
• Volume: 180
• Category: Article
• ISSN: 0026-8925
• DOI: 10.1007/bf00425846

✦ Synopsis

Specialized transducing 2 phages have been isolated which carry the regions of the Escherichia coli chromosome containing the gene or gene-clusters for ribosomal proteins (r-proteins) S 1, $6-S 18-L9, S 16-L 19, and L28-L33. To investigate whether these phages also carry the genes for r-proteins $9, L 13, L20, L31, and L34 whose gene locations are not known, cells irradiated with UV light were infected with these phages and the r-proteins synthesized were analyzed by two-dimensional gel electrophoresis. However, no synthesis of these r-proteins was stimulated, indicating that their genes are not located in the neighborhood of any of the above-mentioned genes or gene clusters. It was found that proteins $6 and S 18 synthesized in the cells irradiated with UV light were not modified under these conditions in which no concomitant ribosome assembly took place.

To investigate whether the genes for the five rproteins mentioned above are located in the regions of the E. coli chromosome where we mapped the genes for those r-proteins that were electrophoretically distinguishable from wild-type proteins (Isono et al. 1976, 1977, 1978), we have isolated specialized transducing 2 phages carrying these chromosomal regions (see Fig. 1). In addition, we have isolated a transducing 2 phage carrying the gene for protein S 1 which was recently mapped near serC (Ono et al. 1979). These phages were then used to infect cells irradiated with UV light to examine whether they stimulated the synthesis of the above-mentioned five r-proteins. The results reported in this paper suggest that none of the five r-protein genes is present on the transducing 2 phages that were isolated and tested.

Earlier studies have shown that proteins $6 and S18 undergo post-translational modification (Reeh and Pedersen 1979;Yaguchi 1975). During the course