Contact with a component of the polymerase II holoenzyme suffices for gene activation.
In yeast strains bearing the point mutation called GAL11P (for potentiator), certain GAL4 derivatives lacking any classical activating region work as strong activators. The P mutation confers upon GAL11, a component of the RNA polymerase II holoenzyme, the ability to interact with a portion of the dimerization region of GAL4. The region of GAL11 affected by the P mutation is evidently functionally inert in ordinary cells, suggesting that this mutation is of no functional significance beyond creating an artificial target for the GAL4 dimerization fragment. From these observations and further analyses of GAL11, we propose that a single activator-holoenzyme contact can trigger gene activation simply by recruiting the latter to DNA.
Barberis
A
A
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Pearlberg
J
J
Simkovich
N
N
Farrell
S
S
Reinagel
P
P
Bamdad
C
C
Sigal
G
G
Ptashne
M
M
D004271:DNA, Fungal / Q000378:metabolism; D004268:DNA-Binding Proteins; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D056892:Mediator Complex; D008957:Models, Genetic; D016296:Mutagenesis; D017354:Point Mutation; D011485:Protein Binding; D012319:RNA Polymerase II / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D015003:Yeasts / Q000201:enzymology / Q000235:genetics*
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C058337:GAL11 protein, S cerevisiae; C052130:GAL4 protein, S cerevisiae; D056892:Mediator Complex; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D012319:RNA Polymerase II