Inducible expression of double-stranded RNA directs specific genetic interference in Drosophila.
BACKGROUND
The introduction of double-stranded RNA (dsRNA) can selectively interfere with gene expression in a wide variety of organisms, providing an ideal approach for functional genomics. Although this method has been used in Drosophila, it has been limited to studies of embryonic gene function. Only inefficient effects have been seen at later stages of development.


RESULTS
When expressed under the control of a heat-inducible promoter, dsRNA interfered efficiently and specifically with gene expression during larval and prepupal development in Drosophila. Expression of dsRNA corresponding to the EcR ecdysone receptor gene generated defects in larval molting and metamorphosis, resulting in animals that failed to pupariate or prepupae that died with defects in larval tissue cell death and adult leg formation. In contrast, expression of dsRNA corresponding to the coding region of the betaFTZ-F1 orphan nuclear receptor had no effect on puparium formation, but led to an arrest of prepupal development, generating more severe lethal phenotypes than those seen with a weak betaFTZ-F1 loss-of-function allele. Animals that expressed either EcR or betaFTZ-F1 dsRNA showed defects in the expression of corresponding target genes, indicating that the observed developmental defects are caused by disruption of the genetic cascades that control the onset of metamorphosis.


CONCLUSIONS
These results confirm and extend our understanding of EcR and betaFTZ-F1 function. They also demonstrate that dsRNA expression can inactivate Drosophila gene function at later stages of development, providing a new tool for functional genomic studies in Drosophila.
Lam
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Howard Hughes Medical Institute, Department of Human Genetics, University of Utah, Salt Lake City 84112-5331, USA.
Thummel
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D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins; D004440:Ecdysone / Q000378:metabolism; D051717:Fushi Tarazu Transcription Factors; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins; D006358:Hot Temperature; D019476:Insect Proteins; D008675:Metamorphosis, Biological / Q000235:genetics*; D008969:Molecular Sequence Data; D012330:RNA, Double-Stranded / Q000235:genetics / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid / Q000235:genetics* / Q000378:metabolism; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D019476:Insect Proteins; D012330:RNA, Double-Stranded; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C055469:ecdysone receptor; C497169:ftz protein, Drosophila; C499712:nuclear hormone receptor FTZ-F1, Drosophila; D004440:Ecdysone