A conserved role for the zinc finger polyadenosine RNA binding protein, ZC3H14, in control of poly(A) tail length

Neuron-specific expression of ZC3H14-iso1 but not ZC3H14-iso4 is sufficient to rescue organismal and functional defects of dNab2^null flies. (A) Normal wing posture is shown in control (denoted “wildtype”) adult flies. dNab2 null mutants with UAS-ZC3H14 transgenes but lacking a Gal4 driver (UAS-ZC3H14-iso1^Flag/+;;dNab2^ex3/dNab2^ex3, or UAS-ZC3H14-iso4^Flag/+;;dNab2^ex3/dNab2^ex3 denoted as “no driver”) display a fully penetrant wings-held-out phenotype, which is rescued in dNab2 null flies transgenically expressing ZC3H14-iso1 in all neurons (elav-GAL4/UAS-ZC3H14-iso1^Flag;;dNab2^ex3/dNab2^ex3, denoted as “in neurons”) but not in dNab2^null flies expressing ZC3H14-iso4 in all neurons (elav-Gal4/UAS-ZC3H14-iso4^Flag;;dNab2^ex3/dNab2^ex3, denoted as “in neurons”). (B) Thoracic bristle kinking in dNab2^nulladults is not rescued by neuronal expression of ZC3H14 isoforms. Dorsal views of the thorax are shown. Genotypes are the same as listed in A. Wild-type (wildtype) flies have straight extended bristles, but dNab2^null flies containing UAS-ZC3H14-iso1 (ZC3H14-Iso1) or UAS-ZC3H14-iso4 (ZC3H14-Iso4) with (in neurons) or without (no driver) the neuronal elav-Gal4 driver still show bristle kinking (denoted by white arrows). Thus, neuron-specific expression of ZC3H14-iso1 or ZC3H14-iso4 does not rescue bristle kinking. (C) A negative geotaxis assay (Ganetzky and Flanagan 1978) was used to assess locomotor activity in flies with the following genotypes (wt=+/+, dNab2 null=ex3/ex3, “+iso1 [in neurons]”= elav-Gal4/UAS-iso1;;ex3/ex3, “+iso1 [no driver]”= UAS-iso1/+;;ex3/ex3, “+iso4 [in neurons]”= elav-Gal4/UAS-iso4;;ex3/ex3, “+iso4 [no driver]”= UAS-iso4/+;;ex3/ex3). Data are presented as the average percentage of flies reaching the top of a cylinder (% at top) at indicated time points across all trials. At least 10 independent trials each containing 10 flies were tested for all genotypes, except ZC3H14-iso4 expressing flies in which two groups of 10 flies were analyzed due to the low frequency of adults obtained for this genotype. Error bars, SEM. Asterisks denote genotypes in which no flies reached the top of the vial within the parameters of the assay.