Five tandem GAL4 upstream activation sequences with the adenovirus E1B minimal promoter (5×UAS-E1B)

Five tandem copies of the yeast GAL4 upstream activation sequence (UAS) fused to the adenovirus E1B minimal promoter. Produces no transcription on its own; drives expression only in cells that also express a GAL4 transcriptional activator. Core effector half of the Gal4/UAS binary expression system used for tissue-restricted transgene expression in Drosophila melanogaster and Danio rerio.

Length: 167 bp

Strength: inducible

Tissue: None intrinsic to this element — the activity pattern is set entirely by the co-expressed GAL4 driver line, not by the UAS-E1B sequence itself

Expression: inducible

Origin: Synthetic — GAL4 UAS array fused to adenovirus E1B minimal promoter

Characteristics

Inert without a co-expressed GAL4 (or GAL4-VP16) driver, since GAL4 does not activate transcription endogenously in Drosophila or zebrafish; the driver binds the tandem UAS repeats and activates the adjacent E1B minimal promoter in trans (Brand & Perrimon 1993). Output scales with GAL4 activator potency and UAS copy number — the optimized KalTA4 activator produces stronger, more consistent UAS-reporter transactivation than GAL4-VP16, and transgene dosage can be tuned through UAS repeat number (Distel et al. 2009).

Applications: Effector component of the Gal4/UAS binary system for spatially and temporally restricted transgene expression in Drosophila and zebrafish; paired with a tissue-specific GAL4 (or GAL4-VP16) driver line to express fluorescent reporters or effector genes in defined cell populations for developmental and neural-circuit studies (Köster & Fraser 2001; Distel et al. 2009).

Limitations: Cannot function as a standalone promoter — produces no output without a co-expressed GAL4 driver, and its expression pattern is set entirely by that driver's specificity. Tandem UAS repeats are prone to DNA methylation and progressive silencing across generations, worsening with higher UAS copy number and in bicistronic GAL4/UAS layouts (Akitake et al. 2011).

Sequence

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References

  1. Brand et al. (1993). Targeted gene expression as a means of altering cell fates and generating dominant phenotypes. Development - Brand 1993 GAL4 UAS
  2. Köster et al. (2001). Tracing transgene expression in living zebrafish embryos. Dev. Biol. - Köster 2001 Gal4-VP16