Formation and Morphology of Dark Puffs in Drosophila Melanogaster Polytene Chromosomes
| Autor: | V. V. Shloma, I. F. Zhimulev, V. F. Semeshin |
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| Rok vydání: | 2004 |
| Předmět: |
Transcription
Genetic Heterochromatin Transgene Genes Insect Locus (genetics) Chromosomes Animals Genetically Modified chemistry.chemical_compound stomatognathic system Genetics Animals Drosophila Proteins HSP70 Heat-Shock Proteins Promoter Regions Genetic Gene Polytene chromosome biology Chromosome Mapping General Medicine biology.organism_classification Chromosome Banding respiratory tract diseases Housekeeping gene Cell biology Microscopy Electron Drosophila melanogaster Gene Expression Regulation Microscopy Fluorescence Ribonucleoproteins chemistry Larva Insect Proteins sense organs DNA Transcription Factors |
| Zdroj: | Hereditas. 134:15-22 |
| ISSN: | 0018-0661 |
| DOI: | 10.1111/j.1601-5223.2001.00015.x |
| Popis: | The formation of unusual dark puffs in Drosophilu melunoguster polytene chromosomes has been studied by electron microscopic (EM) analysis. Fly stocks transformed by the P[ry; Praf.bw] and P[hs-BRC-zl] constructs were used. In the former the bw gene is under the promoter of a housekeeping gene, Prat; in the latter the Br-C locus, mapping to the dark puff 2B, is under the promoter of a heat-shock gene, hsp 70. Inserted into region 65A of the 3L chromosome, the Praf.bw copies give rise to structures which are morphologically reminiscent of the so-called “dark” puffs. In contrast, insertion of P[hs-BRC-zl] into region 99B of the 3R chromosome causes a regular “light” puff to form. Comparative analysis of the dark puffs – both transgenic and natural – suggests that there might be at least two mechanisms underlying their formation. One is a local incomplete decondensation of activated bands, characteristic of the so-called small puffs. The other is the formation of ectopic-looking contacts between the bands adjacent to the puffing zone. Transposition of the DNA, from which such a puff develops, causes a regular light puff to form at the new location. Heterochromatic regions do not appear to be directly involved in puffing. |
| Databáze: | OpenAIRE |
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