Michael Akam*, Dept, of Genetics, Downing Street, Cambridge CB2 3EH
Products of the bithorax complex (BX-C) control the developmental fate of segments in the Drosophila embryo (Lewis, 1978).
I have localized transcripts from the Ubx (Ultrabithorax) region of the BX-C using in situ hybridization with tritium-labelled probes (Akam, 1983) prepared from cloned genomic fragments of the complex (Bender et al. 1983), encoding the major 5′ exon of the Ubx transcripts.
In the cellular blastoderm, Ubx transcripts accumulate principally in a narrow band of cells approximately midway between anterior and posterior poles of the egg, a location which, from fate mapping, corresponds to the primordia for the third thoracic and/or first abdominal segments.
After gastrulation, Ubx transcripts are detectable in a larger region of the germ band, extending from the third thoracic to the eighth abdominal segments. Both mesoderm and ectoderm are...
