title: Primary structure of the ribosomal DNA intergenic spacer from the mosquito, Aedes albopictus.
abstract: We have determined the primary structure of a 4.7-kb portion of the ribosomal DNA intergenic spacer from cultured cells of the mosquito, Aedes albopictus. Immediately upstream from the 18S rRNA gene was a 753-bp sequence containing two regions similar to known RNA polymerase I promoters, each preceded by potential transcription termination signals. Upstream from this putative promoter region was a 3.15-kb tandem array of 17 direct repeats with a consensus sequence length of 201 bp. The 201-bp repeats contained imperfect antisense duplications of 11-bp core domain regions in the putative RNA polymerase I promoters, and sequences of possible significance in recombination. Farthest upstream of the 18S rRNA gene was an 803-bp region containing two copies each of 34-, 48-, and 64-bp elements separated by apparently unique sequence. This first detailed structural analysis of a ribosomal DNA intergenic spacer from a member of the lower Diptera has revealed features similar to those described for the higher Diptera as well as conserved motifs presumably critical to rRNA transcription.
authors.affiliation: Department of Entomology, University of Minnesota, St. Paul 55108.
authors.forename: G D
authors.initials: GD
authors.lastname: Baldridge
authors.forename: A M
authors.initials: AM
authors.lastname: Fallon
mesh_terms: D000330:Aedes / Q000235:genetics*; D000818:Animals; D016375:Antisense Elements (Genetics); D001483:Base Sequence; D004275:DNA, Ribosomal / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012318:RNA Polymerase I / Q000235:genetics; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D013728:Terminator Regions, Genetic
chemical_list: D016375:Antisense Elements (Genetics); D004275:DNA, Ribosomal; D012318:RNA Polymerase I