One of the themes that keeps popping up here is that of nucleases. I thought I would post an adaptation of a table from a recent review by Ciarán Condon that lists the various ribonucleases in E. coli and B. subtilis. The point is to illustrate the variety of nucleases that exist in bacteria, and to get readers to think more of the importance of RNA processing and, moreso, RNA turnover.
This table is adapted from Condon C (2007), Maturation and degradation of RNA in bacteria, Current Opinion in Microbiology 10: 271–278. Enjoy.
| enzyme | E. coli | B. subtilis | endo/exo |
| PNPase | pnp | pnpA | exo |
| RNase R | rnr | rnr | exo |
| RNase PH | rph | rph | exo |
| YhaM | – | yhaM | exo |
| RNase II | rnb | – | exo |
| RNAse D | rnd | – | exo |
| Oligo-RNase | orn | – | exo |
| RNase T | rnt | – | exo |
| RNase III | rnc | rncS | endo |
| RNase P | rnpAB | rnpAB | endo |
| RNase Z | rbn | mz | endo |
| MazF/EndoA | mazF | ndoA | endo |
| ChpBK | chpBK | – | endo |
| YoeB | yoeB | – | endo |
| RNase E | rne | – | endo |
| RNase G | cafA | – | endo |
| RNase I | rna | – | endo |
| RNase HI | rnhA | – | endo |
| RNase HII | rnhB | rnhB | endo |
| RNase HIII | – | rnhC | endo |
| RNase M5 | – | rnmV | endo |
| RNase Bsn | – | yurI | endo |
| YhcR | – | yhcR | endo |
| RNase J1 | – | rnjA | exo+endo |
| RNase J2 | – | rnjB | exo+endo |
In this table, “exo” = exonuclease and “endo”=endonuclease. Also, cells filled with “-” indicate that the corresponding enzyme is apparently absent from the genome. It is fascinating to see the diversity of nucleases, and the variability in terms of the nuclease “contents” of genomes, even with just these two species.
Hopefully, some of these names ring bells in the minds of readers. I’ve mentioned a few of these in other essays, and some of the others (RNase P, RNase H) may be familiar.
The RNA Underworld 