Subject(s)
Brain Ischemia/pathology , Embolism/pathology , Mitral Valve Insufficiency/pathology , Stroke/pathology , Aged , Brain Ischemia/diagnostic imaging , Calcinosis/pathology , Echocardiography, Transesophageal , Embolism/diagnostic imaging , Female , Humans , Mitral Valve Insufficiency/diagnostic imaging , Ocular Motility Disorders/etiology , Ocular Motility Disorders/pathology , Stroke/diagnostic imaging , Stroke, Lacunar/pathology , Tomography, X-Ray ComputedABSTRACT
The rncS gene of Bacillus subtilis encodes Bs-RNase III, a narrow-specificity endoribonuclease. Previous attempts to disrupt rncS were unsuccessful. Here, a strain was constructed in which Bs-RNase III expression was dependent upon transcription of rncS from a temperature-sensitive plasmid. Growth of this strain at the non-permissive temperature resulted in 90-95% cell death, and virtually all the cells that survived retained the rncS-expressing plasmid. Thus, we conclude that rncS is essential in B. subtilis. The rncS conditional strain also revealed that Bs-RNase III participates in the processing of ribosomal RNA, in addition to processing small cytoplasmic RNA, a member of the signal recognition particle RNA family. Most significantly, a rare rncS null strain was isolated that will aid further study of the critical role Bs-RNase III plays in B. subtilis.
