Although Arg and Arg did not participate in contacting the RNA/DNA template, mutations of these residues resulted in a marked decrease in catalytic activity.
P157, which corresponds to the Q in region 4 of DGR RTs, is considered part of the template grip; mutations in this residue also affect nucleotide incorporation patterns [ 22, 23].
RNA templates carrying mutations in the U5-IR stem and loop were constructed to examine reverse transcription in vitro.
In addition, mechanistic template mutation matrices (MTMMs) representing oxidative DNA damage, ultraviolet-induced DNA damage, 5mCpG deamination, and APOBEC-mediated cytosine mutation, are presented.
Distinguishing desired mutants from parental template and undesired mutations in SDM is still a problem not well solved.
While similar mechanisms have not yet been shown to occur in multicellular organisms, in ciliates, non-coding RNAs can directly guide DNA rearrangements and serve as a template for assimilation of mutations in the somatic genome (Nowacki, Shetty, & Landweber, [ 16]).
Further transition from a dsRNA to a dsDNA world could be based on minor mutations in template and substrate recognition sites of an RNA polymerase and would leave all existing processes intact.
I designed a 175mer repair template with six silent point mutations in the 20-bp sequence preceding the PAM, as the PAM could not be silently mutated.
In some cases, for example, there were mutations in the template strand, rather than the strand containing the lesion, which suggests that various enzymes had been able to access the template strand during the repair process.
To test this prediction, we measured the frequency of single-base deletion mutations in a template TTTT during DNA synthesis in vitro to fill a 6-nucleotide gap (Bebenek et al, 2003).
