drifter, a Drosophila POU-domain transcription factor, is required for correct differentiation and migration of tracheal cells and midline glia.
The Drosophila drifter (dfr) gene, previously referred to as Cf1a, encodes a POU-domain DNA-binding protein implicated as a neuron-specific regulator in the developing central nervous system (CNS). We have isolated full-length dfr cDNA clones that encode a 46-kD protein containing the conserved POU-domain DNA-binding domain. The use of alternate polyadenylation sites produces two dfr mRNA transcripts that are first expressed in stage 10 embryos at 5- to 6-hr of development. A specific anti-dfr polyclonal antiserum generated against a dfr-glutathione S-transferase fusion protein recognizes a 46-kD protein on Western blots and has been used to analyze the cell-specific distribution of dfr protein during embryonic development. dfr protein is distributed in a complex expression pattern including the tracheal system, the middle pair of midline glia, and selected CNS neurons. We have carried out a genetic characterization of the dfr locus, previously localized to region 65D of the third chromosome, by generating a series of overlapping deficiencies between 65A and 65E1 that were used to isolate dfrE82, an EMS-induced lethal allele. Analysis of dfrE82 mutant embryos shows a disruption of the developing tracheal tree as well as commissural defects in the developing CNS. Based on an examination of a cell-specific marker for tracheal cells and midline glia, these defects appear to be caused by a failure of these cells to follow their characteristic routes of migration. The dfrE82 tracheal phenotype is rescued by a dfr minigene present as a P-element transposon expressing wild-type dfr protein in tracheal cells. These results suggest that the dfr protein plays a fundamental role in the differentiation of tracheal cells and midline glia possibly by regulating the expression of essential cell-surface proteins required for cell-cell interactions involved in directed cell migrations.
Anderson
M G
MG
Department of Physiology and Biophysics, University of Iowa, College of Medicine, Iowa City 52242.
Perkins
G L
GL
Chittick
P
P
Shrigley
R J
RJ
Johnson
W A
WA
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002465:Cell Movement / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics*; D015870:Gene Expression; D017344:Genes, Insect; D005804:Genes, Lethal / Q000235:genetics; D007150:Immunohistochemistry; D009154:Mutation; D009420:Nervous System / Q000166:cytology / Q000196:embryology*; D009457:Neuroglia / Q000502:physiology*; D050809:POU Domain Factors; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014018:Tissue Distribution; D014132:Trachea / Q000002:abnormalities / Q000166:cytology / Q000196:embryology*; D014157:Transcription Factors / Q000235:genetics* / Q000302:isolation & purification
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D050809:POU Domain Factors; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C091575:vvl protein, Drosophila