Functional mapping of the GAGA factor assigns its transcriptional activity to the C-terminal glutamine-rich domain.
GAGA is a nuclear protein encoded by the Trithorax-like gene in Drosophila that is expressed in at least two isoforms generated by alternative splicing. By means of its specific interaction with DNA, GAGA has been involved in several nuclear transactions including regulation of gene expression. Here we have studied the GAGA(519) isoform as a transcription factor. In vitro, the transactivation domain has been assigned to the 93 C-terminal residues that correspond to a glutamine-rich domain (Q-domain). It presents an internal modular structure and acts independently of the rest of the protein. In vivo, in Drosophila SL2 cells, Q-domain can transactivate reporter genes either in the form of GAGA or Gal4BD-Q fusions, whereas a GAGA mutant deleted of the Q-domain cannot. Our results give support to the notion that GAGA can function as a transcription activating factor.
Vaquero
A
A
Departament de Biologia Molecular i Cel.lular, Institut de Biologia Molecular de Barcelona, Centre d'Investigació i Desenvolupament-Consejo Superior de Investigaciones Cientificas, Jordi Girona 18-26, 08034 Barcelona, Spain.
Espinás
M L
ML
Azorin
F
F
Bernueś
J
J
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D004330:Drosophila; D029721:Drosophila Proteins; D004926:Escherichia coli / Q000378:metabolism; D017930:Genes, Reporter; D005973:Glutamine / Q000737:chemistry*; D006367:HeLa Cells; D018398:Homeodomain Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D015533:Transcriptional Activation; D014162:Transfection
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D020033:Protein Isoforms; D014157:Transcription Factors; C063460:Trl protein, Drosophila; D005973:Glutamine; D004247:DNA