EXPRESSION OF DNAK AND GROESL OPERONS DURING SPORULATION OF BACILLUS-MEGATERIUM

Expression of the dnaK and groEL genes during sporulation was assayed by determination of their mRNA levels by Northern blotting and compare d with the relative level and rate of synthesis of the corresponding p roteins. The ability of sporulating cells to respond to a heal shock b y an increase in dnaK and groEL expression was determined at the same time. Synthesis of DnaK and GroEL encoding mRNAs during sporulation in non-shocked cells was low suggesting that this kind of cytodifferenti ation was not accompanied by enhanced synthesis of these chaperones. A lso the ability of sporulating cells to respond to a heat shock by sti mulating their synthesis substantially decreased during the reversible and dropped to negligible values during the irreversible sporulation phase. Nevertheless, some dependence of the hear shock response on spo rulation exists because sporulation suppression by mutation or by netr opsin treatment further decreased the cells' capacity to respond to a heat shock. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.