Expressing the ADAR1p150 (E912A) mutant that inactivates the deaminase catalytic site gave the least effective reduction in ISG levels.
If so, then a mutation that inactivates the mutant protein should revert the dominant suppression of the P[181PRE]8-10C eye color.
However, single deletions of either locus only resulted in a minor effect on bile salt resistance possibly due to mutual compensation of the two loci [ 19], which may also explain why we did not identify these loci in the M-TraM screening, as the mutant library only contains mutants that are inactivated in a single locus by transposon insertion [ 22].
Indeed, upon selection ∼1% of the females were weakly fertile, giving a few escaper F1 progeny harboring a variety of mutant alleles that inactivate the remaining restriction site.
To further examine the role of HJ processing, we analyzed a strain carrying the ruvA60 mutant allele that inactivates the RuvABC HJ resolvasome.
In contrast to Keio mutants, transposon insertion can generate mutations that inactivate more than one gene (e.g., a full operon) and, more importantly, mutations that affect genes at different levels (e.g., mutants that modulate gene expression by insertions in promoter regions [ 26], or mutants with partial gene activity by insertions near the C-terminus of a gene).
The SHO1 gene was initially identified by isolation of mutants that are synthetically high osmolarity sensitive in the presence of mutations that inactivate the Sln1 branch of the HOG pathway (Maeda et al. 1995).
Moreover, we found that expression of RhebQ64L, a constitutively active mutant that inactivates TSC2 and activates mTOR, leads to a dramatic upregulation of Pml protein in p53 null MEFs (Fig 3E).
Deletion of the whole ABD in talin did not impair talin function further, consistent with the dimerization helix being essential for actin binding [ 23, 24], and possibly only necessary for this function, because a point mutant that inactivates actin binding but not dimerization is equivalent to one that impairs both [ 18].
A recent study using several TAM67 mutants that have different binding specificities to AP-1 components indicates that TAM67 likely inactivates Fos family member proteins to suppress cell growth of breast cancer (Lu et al, 2005).
