RegB endoribonuclease is involved in the processing of transcripts from mobD gene cluster of bacteriophage T4

Abstract

Bacteriophage T4 encoded endoribonuclease RegB introduces cuts in the middle of GGAG/U motifs of early phage mRNAs. Analysis of DNA sequence revealed 18 potential cleavage sites for T4 RegB nuclease in genes mobD.5-mobD comprising the mobD gene cluster. Primer extension sequencing of the transcripts from this genomic region showed the existence of seven 5\' ends generated by RegB-dependent cleavage. All but one of them occurred in the middle of the GGAG tetranucleotide. Three newly identified RegB nuclease targets are located in the SD sequences of genes mobD.5, mobD.2 and mobD.1, while the other four are situated within the coding sequences of transcripts for genes mobD.4, mobD.1 and mobD. The primer extension analysis also indicates that most of GGAU motifs escape the processing by RegB. The results show that RegB nuclease efficiently cleaves the transcripts from the mobD gene cluster and thus plays a substantial role in the degradation of transcripts from this genomic region. Keywords: bacteriophage T4, endoribonuclease RegB, mobD gene cluster