It attempts to 'deconstruct' the virus, by eliminating functions that are limiting or undesired, and to rebuild it, either by delegating the missing necessary functions to the host (which is genetically modified to provide those functions) or by replacing them with analogous functions that are not derived from a virus.
Query genes are hypomorphic mutants, with reduced but not eliminated function, of genes corresponding to signaling pathways in metazoans.
In this study, we eliminate function of Shal/Kv4, and the entire somato-dendritic IA current in Drosophila neurons, and perform a detailed characterization of the effects on neuronal firing.
Each of these essentially eliminated function of APC2 in downregulating ßcat levels.
Previous studies using genetic mutations that eliminate function of all isoforms or UNC-13L demonstrate an essential role of UNC-13L in neurotransmitter release (Richmond et al., 1999).
Possibly some of these genes are effectively inactivated due to loss of promoter features or to amino acid replacements that eliminate function of the protein.
Mutation of H4.56 to alanine in either hFFA2 or bFFA2 completely eliminated function (Fig. 5 D), while the H6.55 to alanine mutant retained some activity only in bFFA2 to C5 and 19 (Fig. 5 E).
However, one can also obtain desired gene mutations by using the following processes: targeted mutations that eliminate function in the whole organism or in a specific tissue; forward genetic screens using chemicals or transposons; or the introduction of exogenous transgenes as DNAs, bacterial artificial chromosomes (BACs) or reporter constructs.
One possible explanation of these unexpected results is a failure of the gene targeting to eliminate functioning of the Pygo1 and Pygo2 genes.
The long-term fitness of mutator populations may be low for many reasons, such as their tendency to experience mutations that eliminate functions unneeded in the current environment but essential in future habitats, and their risk of mutational extinction when population size is small [ 30].
