After analyzing the available information about nmo transcripts, I've reached to the conclusion that the transgene included in the P{UAS-nmo.c4-2} construct does not correspond to an isoform actually expressed in flies and probably is the result of an error at the moment of cDNA synthesis.
This construct was made from a clone isolated by Choi and Benzer and encodes a 477 aa protein. However, this protein is not predicted in Drosophila genome, neither in any other Drosophila species, and there's no other EST, besides this clone, that encodes this isoform. Two proteins are
predicted to be encoded by this gene, being 414 and 430 aa long.
The clone sequence (you can find it under the accession U12009.1 in Genbank) is almost completely similar to that of the mRNA that encodes the shortest isoform, but it includes an extra base at the end of the coding region that produces a frame shift. As a result of this shift, the protein has 63 more amino acids than the corresponding predicted protein. This change does not alter the kinase domain, and that might be the reason why this construct shows a wing phenotype similar to that of P{UAS-nmo.c5-1} (extra vein material in L2 when expressed in the wing disc with 69B-gal4).
