Lamprey Dlx gene expression in the forebrain and
pharyngeal arches. Whole mounts and horizontal sections of the head
regions of 15-day-old lamprey embryos labeled with DlxA,
DlxB, DlxC, and DlxD riboprobes.
(A–D, ×150; E–K, ×75.) All four lamprey
Dlx genes are expressed in each pharyngeal arch
(A–D, arrows). Sections reveal that Dlx
transcripts accumulate in the rostrolateral quadrant of the arch
mesenchyme (F, G, I, and K, arrows), the
site of future cartilage condensations. DlxA and
DlxC are expressed in two bilateral pairs of transverse
stripes in the ventral diencephalon and telencephalon (A, C,
E, and H, arrowheads), whereas
DlxD is expressed in a single pair of transverse stripes
in the ventral diencephalon (D and J).
DlxA, DlxB, and DlxC are
also expressed in the olfactory placode (OlfP) and the otic vesicle
(OtV, not shown for DlxC and DlxD).
DlxB is not detected in the forebrain, olfactory
placode, or otic vesicle.