A T is replaced by an A within the splice donor site of intron 5, preventing the proper splicing of exons 5 and 6. The intron sequence introduces a termination codon which would result in truncation of the encoded protein at around 44% of its length.
T9918962A
T is replaced with A within the splice donor site preventing proper splicing and causing early translation termination.
Development of the musculature is inhibited in mutant embryos, and many of the residual muscles have abnormal morphology.
Mef2113 embryos do not show salivary gland migration defects. However, in late embryonic stages the anterior portion of the gut becomes abnormally enlarged. Only two short gastric caecae evaginate and these do not make contact with the salivary glands.
The three persistant larval oblique muscles per hemithorax of Mef265/Mef2113 animals escape from histolysis as in wild-type animals. Splitting of these muscles generally does not occur in Mef265/Mef2113 animals in contrast to wild-type, so that the number of dorsal longitudinal indirect flight muscles is reduced.
In homozygous mutant embryos, normal muscle does not form, and midgut morphology is abnormal. Specification of myoblasts is apparently normal, but myotubes rarely form. Unfused myoblasts eventually undergo extensive apoptotic cell death. Dorsal vessel morphology is normal. The midgut is severely inflated, has failed to elongate and the anterior portion is enlarged resulting in a spherical yolk sac with only two broad gastric caecae. A low percentage of Mef2113/Mef265 progeny survive to adulthood. These survivors are flightless and their dorsal longitudinal muscles are reduced.
