{'fraction_non_alphanumeric': 0.026019080659150044, 'fraction_numerical': 0.014744145706851692, 'mean_word_length': 4.601941747572815, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 1, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Isolation of RNase H Genes That Are Essential for Growth of Bacillus subtilis 168

ABSTRACT Two genes encoding functional RNase H (EC 3.1.26.4 ) were isolated from a gram-positive bacterium, Bacillus subtilis 168. Two DNA clones exhibiting RNase H activities both in vivo and in vitro were obtained from a B. subtilis DNA library. One (28.2 kDa) revealed high similarity to Escherichia coli RNase HII, encoded by the rnhB gene. The other (33.9 kDa) was designated rnhC and encodes B. subtilisRNase HIII. The B. subtilis genome has anrnhA homologue, the product of which has not yet shown RNase H activity. Analyses of all three B. subtilis genes revealed that rnhB andrnhC cannot be simultaneously inactivated. This observation indicated that in B. subtilis both thernhB and rnhC products are involved in certain essential cellular processes that are different from those suggested by E. coli rnh mutation studies. Sequence conservation between the rnhB and rnhC genes implies that both originated from a single ancestral RNase H gene. The roles of bacterial RNase H may be indicated by the singlernhC homologue in the small genome ofMycoplasma species.