Class II fu allele, affects the carboxy domain of the protein by changing the open reading frame in the 5' region.
Su(fu)LP, fuRX1 has wing blade anterior compartment phenotype
Su(fu)LP, fuRX1 has leg anterior compartment phenotype
Su(fu)LP, fuRX1 has haltere anterior compartment phenotype
When in combination with Su(fu)LP heterozygotes individuals die as pupae. Adult escapers display wings, halteres and legs that have duplication of structures in the anterior compartment and shortening along the proximal-distal axis. Embryos derived from heterozygotes with Su(fu) mutants display a segment polarity phenotype: thoracic denticle belts are absent, last two rows of abdominal denticle belts are absent and a mirror image duplication of anterior rows of abdominal denticle belts.