Molecular analysis of cis-regulatory sequences of the alpha-amylase gene in D. melanogaster: a short 5'-flanking region of Amy distal gene is required for full expression of Amy proximal gene.
The structural locus for alpha-amylase (AMY) in Drosophila melanogaster is duplicated and divergently transcribed. These two genes are designated as Amy-p and Amy-d, respectively. We searched for the cis-acting regulatory elements for full expression of the duplicated Amy-p and Amy-d loci, by injecting plasmid constructs containing sequences from the Amy locus into preblastoderm embryos of an AMY-null strain and measuring exogenous AMY activity produced in transformed host larvae (i.e., the transient expression assay). Relative activities of endogenous amylase isozymes, AMY-1 and AMY-3, in extracts of AMY1,3 larvae of a Canton-S are almost the same. However, three independently isolated Amy-p1 constructs with only the 5' upstream regions of Amy-p1 expressed a very low AMY-1 activity. Two other Amy-p1 constructs with the 5' upstream region of Amy-d3 in addition to that of Amy-p1 produced a high activity. Thus, the 5' upstream region of Amy-d3 is necessary for full expression of Amy-p1. In order to locate cis-regulatory elements within the 5' region of Amy-d3, a series of hybrid constructs including this region were tested to locate them. Our results clearly show that the cis-acting regulatory sequences required for full expression of Amy-p1 are located between the base pairs at -304 and -372 upstream of Amy-d3 gene. In other words, only a short region located upstream of Amy-d3 was found to be necessary and sufficient for the full expression of Amy-p1 in addition to its promoter. This region seems also necessary for the expression of Amy-d3.
Choi
J
J
Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
Yamazaki
T
T
D000818:Animals; D001483:Base Sequence; D004331:Drosophila melanogaster / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D017344:Genes, Insect; D005809:Genes, Regulator; D007527:Isoenzymes / Q000378:metabolism; D008969:Molecular Sequence Data; D010957:Plasmids; D012045:Regulatory Sequences, Nucleic Acid; D000516:alpha-Amylases / Q000235:genetics* / Q000378:metabolism
D007527:Isoenzymes; D000516:alpha-Amylases