Imprecise excision of the progenitor insertion. 261bp of the original insertion, plus a 9bp duplication of the insertion site, remain. The inserted fragment contains a stop codon, leading to a truncation of the moi protein.
In moiM12 homozygous larvae, neuroblasts exhibit telomeric fusions, particularly in autosomes.
Mitotic cells from the brains of homozygous larvae show frequent telomere fusions.
The lesion in the moiM12 mutant is in the upstream ORF (moi) of a dicistronic locus that encodes moi (upstream ORF) and tatl (downstream ORF). The telomere fusion and lethal phenotypes of moiM12 homozygotes are fully rescued by a transgene containing only the moi ORF, indicating that the lesion appears to affect only moi and not tatl.
Allelic series (with respect to severity of telomere fusion phenotype): moi1 > moiCB02140 = moiM12 > moiS096713.