The relationship between the prothrombin upstream sequence element and the G20210A polymorphism: the influence of a competitive environment for mRNA 3'-end formation

Abstract

The human prothrombin G20210A polymorphism located at the 3′ cleavage site of the mRNA results in elevated plasma prothrombin levels and increased risk of venous thrombosis. This polymorphism has been shown to directly influence a variety of processes related to prothrombin mRNA metabolism. We have constructed plasmids that express the full-length prothrombin mRNA that is polyadenylated at its natural site. The A allele prothrombin variant was more efficient than the G allele at promoting cleavage at this site in the presence of a competing poly (A) sequence. In the absence of competition, both allelic variants give rise to a similar level of cleavage site heterogeneity. An upstream sequence element (USE) was also identified within the prothrombin 3′-UTR. When placed upstream of two competing poly (A) sites, the USE directed cleavage preferentially to the proximal poly (A) site. In the absence of competition, the USE had no effect on cleavage site selection. This study suggests that the basis for the increase in prothrombin expression in A allele carriers is not due to allelic changes in cleavage site selection per se. In addition, the functionality of USEs needs to be considered within the context of endogenous sequence architecture.

A systematic analysis of disease-associated variants in the 3′ regulatory regions of human protein-coding genes I: general principles and overview

“…This indeed turned out to be the case, as has been demonstrated by several in vitro studies (Gehring et al 2001;Pollak et al 2002;Ceelie et al 2004;Danckwardt et al 2004;Sachchithananthan et al 2005). Thus, in the words of Danckwardt et al (2004), ''the physiological G at the cleavage site at position 20210 is the functionally least efficient nucleotide to support 3¢ end processing but has evolved to be physiologically optimal''.…”

Hu Proteins Regulate Polyadenylation by Blocking Sites Containing U-rich Sequences

“…In light of another recent discovery (7) that CFIm68 binds to a number of USE sequences containing UGUAN repeats and promotes polyadenylation and that the SVL poly(A) site contains such repeats, it remains a formal possibility that Hu proteins and CFIm may modulate the polyadenylation activity of sites that contain binding sites for both proteins through their competing activities. Given that USEs have been identified in an increasing number of cellular poly(A) sites (23,(35)(36)(37)(38)(39)(40), it will be of particular interest to further investigate the role of Hu proteins in USE-mediated polyadenylation regulation.…”

The prothrombin 20209 C→T mutation in Jewish‐Moroccan Caucasians: molecular analysis of gain‐of‐function of 3′ end processing

“…The underlying molecular mechanism of F2 20210*A and F2 20221*T has previously been identified to represent gain‐of‐function of 3′ end mRNA formation as a novel molecular principle, causing gene dysfunction and a hereditary disorder [9–12]. Furthermore, the F2 20210*A mutation may also affect translation efficiency [13] and, more recently, the unusual susceptibility to gain‐of‐function mutations has been explained by a unique architecture of tightly balanced non‐canonical‐positive and ‐negative elements within the F2 3′ end formation signal (see below) [12,14].…”