mirror encodes a novel PBX-class homeoprotein that functions in the definition of the dorsal-ventral border in the Drosophila eye

Genes Dev. 1997 Apr 15;11(8):1073-82. doi: 10.1101/gad.11.8.1073.


The Drosophila eye is composed of dorsal and ventral mirror-image fields of opposite chiral forms of ommatidia. The boundary between these fields is known as the equator. We describe a novel gene, mirror (mrr), which is expressed in the dorsal half of the eye and plays a key role in forming the equator. Ectopic equators can be generated by juxtaposing mrr expressing and nonexpressing cells, and the path of the normal equator can be altered by changing the domain of mrr expression. These observations suggest that mrr is a key component in defining the dorsal-ventral boundary of tissue polarity in the eye. In addition, loss of mrr function leads to embryonic lethality and segmental defects, and its expression pattern suggests that it may also act to define segmental borders. Mirror is a member of the class of homeoproteins defined by the human proto-oncogene PBX1. mrr is similar to the Iroquois genes ara and caup and is located adjacent to them in this recently described homeotic cluster.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Body Patterning
  • Cloning, Molecular
  • DNA-Binding Proteins / genetics
  • Drosophila / embryology*
  • Drosophila / genetics
  • Drosophila Proteins*
  • Eye Proteins / genetics
  • Eye Proteins / physiology*
  • Gene Expression Regulation, Developmental
  • Genes, Insect / genetics
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Molecular Sequence Data
  • Mutation
  • Photoreceptor Cells, Invertebrate / embryology*
  • Pre-B-Cell Leukemia Transcription Factor 1
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins / genetics
  • RNA, Messenger / analysis
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Transcription Factors*


  • DNA-Binding Proteins
  • Drosophila Proteins
  • Eye Proteins
  • Homeodomain Proteins
  • MAS1 protein, human
  • Pre-B-Cell Leukemia Transcription Factor 1
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins
  • RNA, Messenger
  • Transcription Factors
  • mirr protein, Drosophila
  • pbx1 protein, human

Associated data

  • GENBANK/U95021