Fig. 6. Late, but not early, muscle defects in moz mutants. (A,B)
eng2 expression in wild types marks the dorsal first arch myogenic
core, CD, which is not homeotically duplicated in moz mutants. (C-F)
myod expression in wild type (C,E) and moz mutants (D,F) at
44 hpf (C,D) and 54 hpf (E,F). (C,D) myod expression marks three
first arch and two second arch myogenic cores. The moz mutant second
arch pattern at this stage appears normal. (E,F) By 54 hpf moz mutant
musculature looks aberrant. A small ectopic patch of myod is present
in the intermediate second arch (arrow in F). (G,H) Lateral views of
-tropomyosin expression in wild type (G) and moz mutant (H).
In wild types (G), a large jaw closing muscle (am) connects the upper and
lower jaw. moz mutants appear to have an ectopic jaw closer muscle
(am') in their second arch (H). This muscle appears continuous with what
we interpret to be the remnants of the dorsal (AH and AO) and ventral muscles
(IH and HH) and the first arch dorsal muscles (LAP and DO) appear to not have
segregated as they have in wild types. An enlarged third arch muscle is
present (white arrow in H) in moz mutants. AH, adductor
hyomandibulae; AM, adductor mandibulae; AO, adductor operculi; DO, dilator
operculi; HH, hyohyal; IH, interhyal; IMA, intermandibularis anterior; IMP,
intermandibularis posterior; LAP, levator arcus palatini. Scale bars: 50
µm.