Y. Graba et al., DWNT-4, A NOVEL DROSOPHILA WNT GENE ACTS DOWNSTREAM OF HOMEOTIC COMPLEX GENES IN THE VISCERAL MESODERM, Development, 121(1), 1995, pp. 209-218
Wnt genes encode putative cell signalling proteins which play crucial
roles during development. From a library of DNA fragments associated,
in vivo, with Ultrabithorax proteins, we isolated a novel Drosophila W
nt gene, DWnt-4. Neither a paralog nor an ortholog of the gene exist i
n the current repertoire of full-length Wnt sequences. DWnt-4 maps clo
se (30 kb) to wingless, suggesting that the two Wilt genes derive from
a duplication that occurred early in evolution, since they are signif
icantly diverged in sequence and structure. Developmental expression o
f DWnt-4 partially overlaps that of wingless. The gene is transcribed
following a segment polarity-like pattern in the posterior- most cells
of each parasegment of the ectoderm, and at two locations that corres
pond to parasegments 4 and 8 of the visceral mesoderm. The control of
DWnt-4 expression in the visceral mesoderm involves a network of regul
atory molecules that includes Ultrabithoras and other proteins from th
e homeotic complex (HOM-C), as well as the TGF-beta decapentaplegic ge
ne product.