Figure 11-32. Examples of the complex tissue-specific regulation of the dpp gene.

Figure 11-32

Examples of the complex tissue-specific regulation of the dpp gene. In parts a, c, and d, the blue staining is due to a histochemical assay for E. coli β-galactosidase activity (the protein encoded by the lacZ reporter gene). The map positions of the dpp enhancers responsible for the staining patterns seen here are shown in Figure 11-30. (a) Reporter-gene assay for expression of the Drosophila dpp gene in two parts of the embryonic visceral mesoderm, the precursor of the gut musculature. The left-hand block of blue staining indicates the enhancer VM1, which drives anterior visceral mesoderm expression; the right-hand block of staining indicates the enhancer VM2, which drives posterior visceral mesoderm expression. (b) RNA in situ hybridization assay of dpp expression in the embryonic visceral mesoderm. Note that the blue reporter-gene expression pattern in part a is the same as the brown dpp RNA expression pattern shown here, confirming the reliability of the reporter-gene assay. (c) Reporter-gene expression driven by a different enhancer (LE) of dpp in the lateral ectoderm of an embryo. (d) Reporter-gene expression driven by ID, one of many enhancer elements driving imaginal disk expression of dpp. (An imaginal disk is a flat circle of cells in the larva that gives rise to one of the adult appendages.) A blue sector of dpp reporter-gene expression in a leg imaginal disk is shown. (Parts a and b courtesy of D. Hursh; part c courtesy of R. W. Padgett; part d courtesy of R. Blackman and M. Sanicola.)

From: Transcription: an overview of gene regulation in eukaryotes

Cover of An Introduction to Genetic Analysis
An Introduction to Genetic Analysis. 7th edition.
Griffiths AJF, Miller JH, Suzuki DT, et al.
New York: W. H. Freeman; 2000.
Copyright © 2000, W. H. Freeman and Company.

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