Human ubiquitin C (UBC) promoter
Constitutive promoter from the human ubiquitin C gene; provides stable expression across most mammalian cell types, including tissues such as liver and brain where the CMV, H2-Kb, and Pgk-1 promoters commonly show restricted or low activity. Widely used in lentiviral, AAV, and transgenic constructs requiring broad tissue coverage.
Origin: Human UBC gene 5′-flanking region (natural)
Characteristics
The 1.2 kb human UbC 5'-flanking region (positions -1225 to -6) drives constitutive expression confirmed across all examined mouse tissues, including liver and brain, where CMV, H2-Kb, and Pgk-1 promoters show restricted or low activity; transgene levels reach up to 20-fold above the endogenous transcript in some tissues (Schorpp et al. 1996). In a side-by-side lentiviral GFP reporter comparison across eight mammalian cell lines, UBC is consistently the weakest of six constitutive promoters tested, weaker than PGK, EF1α, CAGG, CMV, and SV40 (Qin et al. 2010).
Applications: Used to drive constitutive transgene expression in transgenic mice (junB, bcl-2α), with confirmed activity from embryonic day 10.5 through adulthood across all examined tissues (Schorpp et al. 1996); also used in lentiviral and AAV vectors for long-term expression in dividing and non-dividing mammalian cells, including liver and brain.
Limitations: Weakest of six constitutive promoters in a head-to-head lentiviral GFP comparison across eight cell lines, driving less expression than CMV, EF1α, PGK, CAGG, and SV40 (Qin et al. 2010); an agent needing maximal expression level should consider EF1α or CAGG instead.
Sequence
References
- Schorpp et al. (1996). The Human Ubiquitin C Promoter Directs High Ubiquitous Expression of Transgenes in Mice. Nucleic Acids Res - Schorpp 1996 UbC Promoter
- Qin et al. (2010). Systematic Comparison of Constitutive Promoters and the Doxycycline-Inducible Promoter. PLoS ONE - Qin 2010 Promoter Comparison