In vivo analysis of the helix-turn-helix motif of the fushi tarazu homeo domain of Drosophila melanogaster.
We report a systematic mutational analysis of the helix-turn-helix motif (HTH) of the fushi tarazu (ftz) homeo domain (HD) of Drosophila. We started out by testing the function of chimeric ftz proteins containing either a part of the Sex combs reduced (Scr) or the muscle segment homeobox (msh) HDs. By complementation tests in transgenic flies, cotransfection assays in cultured Drosophila cells and in vitro DNA-binding assays, we have found that the ftz activity is retained in the ftz-Scr chimera but is lost in the ftz-msh chimera, which is defective in binding to an Antennapedia (Antp)-class target site. Further studies with a series of back-mutants of the ftz-msh chimera have revealed that a set of class-specific DNA backbone-contacting residues in the HTH, particularly Arg-28 and Arg-43, are required for efficient target site recognition and, hence, full ftz activity both in vitro and in vivo.
Department of Cell Biology, University of Basel, Swtizerland.
K
K
Furukubo-Tokunaga
M
M
Müller
M
M
Affolter
L
L
Pick
U
U
Kloter
W J
WJ
Gehring
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D004251:DNA Transposable Elements / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D051717:Fushi Tarazu Transcription Factors; D005801:Genes, Homeobox; D005816:Genetic Complementation Test; D018398:Homeodomain Proteins; D007301:Insect Hormones / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D004251:DNA Transposable Elements; D029721:Drosophila Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D007301:Insect Hormones; D011993:Recombinant Fusion Proteins; C497169:ftz protein, Drosophila; D004247:DNA