Ribosome Genetics Revealed by Hybrid Bacteria

Abstract

INTRODUCTION
Genetic mosaicism in plants and animals has made it possible to study problems of chromosome linkage and gene action that otherwise could not be approached experimentally. An extension of this natural phenomenon has been the production of hybrids between the somatic cells of different animals. Certain hybrid cell lines have made it possible to assign specific genes to a given chromosome or chromosome group (Weiss and Green 1967; Matsuya, Green and Basilico 1968). As a general technique, hybrid cells may be useful for mapping the genes which control essential functions, especially where there are no apparent methods for selecting conditional (i.e., temperature-sensitive) mutations.

The possibility that genetic hybrids could be used to map the genes for ribosomal proteins and RNA was first suggested by the studies of Leboy, Cox and Flaks (1964). In studying the differences that occur naturally between the ribosomal proteins of Escherichia coli strains, they showed that one protein had a different electrophoretic mobility in strain K12 from its counterpart in strain B. The genetic determinant for this protein (the “K character”) was shown to be linked to the locus controlling streptomycin resistance (strA) when crosses between the two strains were performed.

Mapping the Genes for Ribosomal Proteins
Naturally occurring differences in the chromatographic behavior of ribosomal proteins from different E. coli strains were investigated further by Osawa and his colleagues. Takata, Dekio and Osawa (1969) found that in addition to the “K character,” or protein S7, the 30S protein S5 of E. coli K12 could...