Functional study of Lactococcus lactis RNase III in Escherichia coli

Endoribonuclease III (RNase III) is known to participate in a number of RNA maturation and decay pathways. Previous research carried out on citQRP mRNA processing had provided strong evidence that RNase III exists in Lactococcus lactis and acts as a major endoribonuclease in the control of citQRP mRNA stability. The DNA coding (rnc) for the putative lactococcal RNase III was cloned by PCR technology. In addition, we provide the transcriptional analysis of rnc gene and compared the lactococcal RNase III sequence to those of Gram-positive and Gram-negative organisms. This computer-assisted comparison showed an identity ranking from 37% to 54%, and the highest score was obtained with Streptococcus pneumoniae RNase III. Moreover, heterologous complementation indicated that lactococcal RNase III is able to complement the loss of Escherichia coli RNase III for both 30S RNA processing and lambda N posttranscriptional regulator.