A shift down in temperature causes in Streptomyces aureofaciens a transient repression of polypeptide synthesis. During the acclimation phase 32 proteins were synthesized. The addition of tetracycline (200 microg/ml) to cells from exponential phase of growth leads to induction of 27 novel proteins and 17 upregulated proteins migrated in 2-D gel as proteins expressed upon cold shock. Immunoblot analysis using antibodies raised against CspB, CspC, and CspD of Bacillus subtilis revealed five cross-reactive proteins of the Csp family. Proteins CspB and CspD are predominantly induced at low temperature or by the presence of tetracycline. Expression of Csp proteins during the acclimation phase is regulated on the transcription level. Proteins of the Csp family have been shown to be associated with ribosomes and can be removed by 1 M NH(4)Cl. As expression of Csp proteins differs during development or temperature shift down, these proteins can be considered as trans-acting factors to form contacts with the coding region of specific mRNAs.

Institute of Microbiology Academy of Sciences of the Czech Republic Vídenská 1083 Prague 4 142 20 Czech Republic

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General and molecular microbiology and microbial genetics in the IM CAS

tmRNA abundance in Streptomyces aureofaciens, S. griseus and S. collinus under stress-inducing conditions