Analysis of subtelomeric heterochromatin in the Drosophila minichromosome Dp1187 by single P element insertional mutagenesis.
We investigated whether single P element insertional mutagenesis could be used to analyze heterochromatin within the Drosophila minichromosome Dp1187. Forty-five insertions of the P[lacZ,rosy+] element onto Dp1187 (recovered among 7,825 transpositions) were highly clustered. None was recovered in centromeric heterochromatin, but 39 occurred about 40 kb from the distal telomere within a 4.7-kb hotspot containing tandem copies of a novel 1.8-kb repetitive DNA sequence. The DNA within and distal to this region lacked essential genes and displayed several other properties characteristic of heterochromatin. The rosy+ genes within the inserted transposons were inhibited by position-effect variegation, and the subtelomeric region was underrepresented in polytene salivary gland cells. These experiments demonstrated that P elements preferentially transpose into a small subset of heterochromatic sites, providing a versatile method for studying the structure and function of these chromosome regions. This approach revealed that a Drosophila chromosome contains a large region of subtelomeric heterochromatin with specific structural and genetic properties.
Karpen
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Howard Hughes Medical Institute Research Laboratories, Carnegie Institution of Washington, Department of Embryology, Baltimore, Maryland 21210.
Spradling
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D000818:Animals; D001483:Base Sequence; D002875:Chromosomes / Q000648:ultrastructure*; D004251:DNA Transposable Elements; D004330:Drosophila / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006570:Heterochromatin; D008297:Male; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional
D004251:DNA Transposable Elements; D006570:Heterochromatin