The Drosophila microRNA iab-4 causes a dominant homeotic transformation of halteres to wings.
The Drosophila Bithorax Complex encodes three well-characterized homeodomain proteins that direct segment identity, as well as several noncoding RNAs of unknown function. Here, we analyze the iab-4 locus, which produces the microRNAs iab-4-5p and iab-4-3p. iab-4 is analogous to miR-196 in vertebrate Hox clusters. Previous studies demonstrate that miR-196 interacts with the Hoxb8 3' untranslated region. Evidence is presented that miR-iab-4-5p directly inhibits Ubx activity in vivo. Ectopic expression of mir-iab-4-5p attenuates endogenous Ubx protein accumulation and induces a classical homeotic mutant phenotype: the transformation of halteres into wings. These findings provide the first evidence for a noncoding homeotic gene and raise the possibility that other such genes occur within the Bithorax complex. We also discuss the regulation of mir-iab-4 expression during development.
Ronshaugen
Matthew
M
Department of Molecular and Cell Biology, Division of Genetics, Center for Integrative Genomics, University of California, Berkeley, 94720, USA.
Biemar
Frédéric
F
Piel
Jessica
J
Levine
Mike
M
Lai
Eric C
EC
D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D004330:Drosophila; D029721:Drosophila Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D017344:Genes, Insect / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family / Q000502:physiology; D009154:Mutation; D014157:Transcription Factors / Q000378:metabolism*; D014921:Wings, Animal / Q000196:embryology*
D020413:3' Untranslated Regions; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D035683:MicroRNAs; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; C580822:iab-4 microRNA, Drosophila