Part:BBa_K404104

p5-TATAless promoter

p5-TATA-less promoter
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BioBrick Nr.	K404104 BBa K404104
RFC standard	RFC 10
Requirement	pSB1C3
Source	pAAV_RC from Stratagene
Submitted by	[http://2010.igem.org/Team:Freiburg_Bioware FreiGEM 2010]

In contrast to the natural location of the p5 promoter, the iGEM team Freiburg 2010 provides the RepCap plasmid with a relocated p5 promoter downstream of the RepCap genes (Figure 1). Additionally the p5 promoter lacks the TATA box element (AVIGEN 1997). Those modifications result in an attenuated expression of the larger Rep proteins therefore leading to normal transcription of the Rep proteins driven by p19 promoter and enhanced expression of the Cap proteins, which are under the control of the p40 promoter. Additionally, removing the p5 promoter downstream of the RepCap genes and deletion of the TATA box eliminates contamination with wtAAVs. Hence, alteration of the p5 promoter is useful for enhanced production of recombinant viral particles attenuating repression of Rep78/68 and improving gene transcription of the capsid proteins and Rep proteins involved in genome packaging.

Figure 1: T: p5 TATA-less promoter is located downstream of the rep and cap ORF..

Containing two consensus sequences for binding immediate early E1A gene product from adenoviruses (Chang et al. 1989), p5 promoter is transactivated in the presence of helper viruses whereas suppression occurs in absence of adenoviral proteins by low levels of Rep proteins (Beaton et al. 1989). Regulating of Rep78/68 by its negative feedback loop is critical since overexpression leads to cell cycle arrest in the S-phase (Berthet et al. 2005) and suppression of cellular promoters (Jing et al. 2001).