EMBRYONIC EXPRESSION PATTERNS OF THE DROSOPHILA DECAPENTAPLEGIC GENE - SEPARATE REGULATORY ELEMENTS CONTROL BLASTODERM EXPRESSION AND LATERAL ECTODERMAL EXPRESSION

Patterns of decapentaplegic (dpp) transcripts derived from the intact gene were compared to the patterns of transcripts generated by partial dpp transgenes in Drosophila embryos. Sequences closest to the dpp co ding regions, the dpp bin region, were sufficient to express lacZ-tagg ed mRNA in patterns indistinguishable from the patterns of endogenous dpp expression in the dorsal and terminal cells at the blastoderm stag e, in the dorsal ectoderm during germ band elongation, and in narrow s tripes of ectodermal cells along the dorsal edge of the ectoderm and a t the boundary between the lateral and ventral neurogenic regions duri ng germ band shortening. The latter pattern of expression responded to the segment polarity genes naked and wingless. However, these dpp seq uences were not sufficient to drive lacZ-tagged mRNA expression in oth er cells normally expressing dpp, including cells in the gnathal segme nts, the clypeolabrum, the foregut, the midgut visceral mesoderm, and the hindgut. Two separate regulatory regions were found in the dpp bin region. A 479 bp region upstream of the promoter was necessary for th e segmented pattern of expression in the lateral ectoderm and for expr ession in the midgut endoderm. Cis-acting elements in the 2 kbp second intron directed expression in the dorsal and terminal regions of the blastoderm, acted on a heterologous promoter, the P-element promoter, and responded to pattern information derived from the maternal effect dorsal/ventral patterning genes. (C) 1994 Wiley-Liss, Inc.