Fig. 3. Patterns of localization of Ubx, Abd-A and Abd-B on polytene chromosomes of the fat body. (A-C) The patterns after staining with Ubx (A), Abd-A (B) and Abd-B (C) antibodies. All the antibodies give numerous signals along the length of all of the chromosomes with the exception of the chromocenter. (D) Enlarged picture of the BX-C region showing that Ubx is located in the proximal part of the region corresponding to the Ubx locus. (E) Enlarged picture of BX-C region sequentially stained with Abd-A antibodies and in situ hybridized with probes derived from Ubx, abd-A and Abd-B cDNAs. The merged figure clearly shows that the Abd-A signal overlaps with both the abd-A and Abd-B genes, while the Ubx gene appears devoid of signal. (F) Enlarged picture of the BX-C region showing the Abd-B staining pattern. Similar to the Abd-A protein, we observed that Abd-B is located on the abd-A and Abd-B genes but is excluded from Ubx. X, X chromosome; 2L and 2R, left and right arms of the second chromosome; 3L and 3R, left and right arms of the third chromosome; chr, chromocenter.