Studies on the nature and role of polyadenylated RNA in spore development of Bacillus subtilis

Summary cDNA probes synthesized on poly(A)RNAs isolated from sporulating cells of Bacillus subtilis were used for hybridization studies with RNAs derived from cells at different stages of growth and sporulation. It was shown that these cDNAs hybridized only to RNA from sporulating cells. No hybridization was observed if total RNA isolated from vegetative cells or from stationary phase cells of a zero stage asporogenic mutant was used. The hybridization studies also indicate that at each sporulation stage different poly(A)RNA species are synthesized. Furthermore, the hybridization kinetics have clearly demonstrated the existence of three distinct abundance classes of poly(A)RNA similar to those observed in eukaryotic cells. BamHI endonuclease restriction fragments of B. subtilis DNA that were found to hybridize to labeled poly(A)RNA were ligated to the pHV33 vector and hybrid clones that hybridized efficiently to poly(A)RNA were selected. Among these, three have been found to carry the spoOB gene.These results strongly suggest that the appearance of poly(A)RNA can be correlated to the expression of spore genes.