Sculpting of the spliceosomal branch site recognition motif by a conserved pseudouridine

@article{Newby2002SculptingOT,
  title={Sculpting of the spliceosomal branch site recognition motif by a conserved pseudouridine},
  author={Meredith I. Newby and Nancy L. Greenbaum},
  journal={Nature Structural Biology},
  year={2002},
  volume={9},
  pages={958-965}
}
Pairing of a consensus sequence of the precursor (pre)-mRNA intron with a short region of the U2 small nuclear (sn)RNA during assembly of the eukaryotic spliceosome results in formation of a complementary helix of seven base pairs with a single unpaired adenosine residue. The 2′ OH of this adenosine, called the branch site, brings about nucleophilic attack at the pre-mRNA 5′ splice site in the first step of splicing. Another feature of this pairing is the phylogenetic conservation of a… 
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We have investigated electrostatic and surface features of an essential region of the catalytic core of the spliceosome, the eukaryotic precursor messenger (pre-m)RNA splicing apparatus. The
Impact of base pair identity 5' to the spliceosomal branch site adenosine on branch site conformation.
TLDR
In these studies, NMR spectra of a duplex in which 2-aminopurine (2ap), a fluorescent analog of adenine lacking the proposed hydrogen bond donor, was substituted for the branch site A indicated that the substitution does not alter the extrahelical position of the branches site residue; thus, it appears that a hydrogen bond between theAdenine amino group and the R-Y pair is not obligatory for stabilization of theextrahelical conformation.
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TLDR
The development of an orthogonal BS-U2 system in S. cerevisiae in which spliceosomes containing a grossly substituted second-copy U2 snRNA mediate the in vivo splicing of a single reporter transcript carrying a cognate substitution provides a foundation and tool for future mechanistic splicing research.
Dynamic stacking of an expected branch point adenosine in duplexes containing pseudouridine-modified or unmodified U2 snRNA sites.
TLDR
The results highlight the importance of auxiliary factors to achieve the active bulged conformation of the branch site nucleophile for the first step of pre-mRNA splicing.
Interaction between the Spliceosomal Pre-mRNA Branch Site and U2 snRNP Protein p14.
TLDR
It is proposed that the p14-RNA interaction screens charges on the backbone of the branch site during spliceosome assembly as well as binding of p14 to RNA is nonspecific and does not recognize the branch sites.
Characterization of the catalytic activity of U2 and U6 snRNAs.
TLDR
It is shown that RNA X formation is an equilibrium reaction, and that the low yield of the reaction likely reflects an unfavorable equilibrium coefficient, which suggests that the ability to form RNA X might be an intrinsic property of spliceosomal snRNAs.
X-ray structures of U2 snRNA-branchpoint duplexes containing conserved pseudouridines.
TLDR
Structural differences may contribute to the ability of the pseudouridine modification to promote the bulged conformation of the branch site adenosine and to enhance catalysis by snRNAs.
Structural biology: Catalytic spliceosome captured
TLDR
The configuration of the RNA within the spliceosome complex suggests that remodelling occurs before the second step, exon ligation, which would indicate active-site interactions and evolutionary constraints on these non-coding regions.
Proximity of conserved U6 and U2 snRNA elements to the 5′ splice site region in activated spliceosomes
TLDR
Several conserved snRNA regions are close to U+10 in activated spliceosomes, namely the U6 snRNA ACAGAG‐box region, portions of the U 6 intramolecular stem‐loop (U6‐ISL) including a nucleotide implicated in the first catalytic step (U74), and the region of U2 that interacts with the branch point.
Towards understanding the catalytic core structure of the spliceosome.
TLDR
In this review, recent progress towards understanding the structure and function of U2 and U6 RNAs is summarized.
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