Levine M, Hafen E, Garber R L, Gehring W J
EMBO J. 1983;2(11):2037-46. doi: 10.1002/j.1460-2075.1983.tb01697.x.
We have localized transcripts specified by the homeotic Antennapedia (Antp) locus within serial tissue sections of Drosophila embryos and larvae by in situ hybridization. As a hybridization probe we used a 2.2-kb cDNA sequence (903) which is complementary to at least four non-contiguous chromosomal DNA regions within a span of 100 kb derived from the Antp+ locus. The tritiated probe was directly hybridized to frozen tissue sections of wild-type embryos and larvae. Hybridization was first detected to the progenitors of the thoracic segments during the cellularization of the syncytial blastoderm, when embryonic cells first become determined to form particular adult segments. At later embryonic stages the ventral nervous system also becomes labeled in a spatially-restricted manner. Initially, accumulation of transcripts is detected in all thoracic and abdominal ganglia of the ventral cord. Subsequently, the highest concentration of transcripts is detected in the ganglion cells of the mesothorax. Proper development of this segment is known to be affected in individuals homozygous for putative Antp null alleles. In third-instar larvae, hybridization to the different imaginal disks of all three thoracic segments is observed, localized mainly to those regions that will form proximal, cuticular portions of the respective segments. These results are discussed with respect to the role of homeotic genes in the specification of particular anatomical segments.
我们通过原位杂交技术，在果蝇胚胎和幼虫的连续组织切片中定位了由同源异型基因触角足基因（Antp）位点所指定的转录本。作为杂交探针，我们使用了一段2.2 kb的cDNA序列（903），它与源自Antp +位点的100 kb跨度内至少四个非连续染色体DNA区域互补。将氚标记的探针直接与野生型胚胎和幼虫的冷冻组织切片杂交。在合胞体胚盘细胞化期间，当胚胎细胞首次被确定形成特定的成虫节段时，首先检测到杂交信号出现在胸节的祖细胞中。在胚胎后期，腹侧神经系统也以空间受限的方式被标记。最初，在腹神经索的所有胸节和腹节神经节中都检测到转录本的积累。随后，在中胸神经节细胞中检测到最高浓度的转录本。已知在假定的Antp无效等位基因纯合个体中，该节段的正常发育会受到影响。在三龄幼虫中，观察到与所有三个胸节的不同成虫盘的杂交，主要定位在将形成相应节段近端表皮部分的区域。针对同源异型基因在特定解剖节段特化中的作用，对这些结果进行了讨论。
