The instability of the CIA targeting complex upon depletion of single members of this complex is indicated by the red box.
The CASS polymerase is most common in thermophiles, and it is tempting to speculate that the prevalence of this form of the psiRNA pathway has to do with the instability of the psiRNA-target duplex under the high ambient temperatures of these organisms.
The most likely reason for this apparent lack of effect is the relative instability of the nucleic acid in the target tissue over such a long period (cf. [ 12]).
Whether because of protease activity or other unknown reasons, the instability of laccase seems to be specific rather than general, because the same host strain is used for the expression of various proteins, including enzymes, cytokines, and structural proteins [ 33, 35, 44], without noticeable instability of expressed target proteins.
Based upon our data, we predict that the Mlh1- Pms1, Msh2- Msh6 complex prevents the instability of the ade2 -h7.5 minisatellite by targeting and repairing mismatches that can occur at two positions within a repeat.
This could be due to a very low level of expression of the targets or the instability of the cleaved product.
However, these mice are more sensitive to chemical- or γ irradiation-induced genotoxic stress and show genomic instability independent of the exon targeted or genetic background, suggesting that PARP-1 may play an important role in genome maintenance under stress conditions.
If the target protein is toxic to the E. coli host, basal expression of the target gene possibly will result in plasmid instability and/or cell death.
