Evolution of the autosomal chorion cluster in Drosophila. III. Comparison of the s18 gene in evolutionarily distant species and heterospecific control of chorion gene amplification.
We present a total of 6.1 x 10(3) base-pairs of DNA sequences, encompassing the s18 gene and flanking regions within the autosomal chorion cluster of three Drosophila species. Against a background of extensive divergence in the intron and even in parts of the coding region, islands of strong sequence conservation are evident. These are particularly notable in the 5' flanking DNA where they extend to approximately -600 base-pairs from the transcription start site. The most conserved segment of the entire chorion cluster is 71 base-pairs in the s18 5' flanking DNA, which in D. melanogaster is part of a region defined functionally as containing amplification control elements (ACE3 region). Transformation analysis, using chimeric transposons of D. melanogaster and D. grimshawi DNA, revealed that amplification control elements of D. grimshawi can support amplification in D. melanogaster. The functionally defined ACE3 region of D. grimshawi includes the conserved 71 base-pair segment, but also non-conserved sequences further upstream, which apparently enhance amplification.
Swimmer
C
C
Department of Cellular and Developmental Biology, Harvard University, Cambridge, MA 02138.
Fenerjian
M G
MG
Martínez-Cruzado
J C
JC
Kafatos
F C
FC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D004330:Drosophila / Q000235:genetics*; D004527:Egg Proteins / Q000235:genetics*; D005784:Gene Amplification; D005796:Genes; D008969:Molecular Sequence Data; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D004527:Egg Proteins; C015753:chorion proteins