What is a branch point site?

What is a branch point site?

The branch site is a short motif upstream of the polypyrimidine tract that includes a BP adenosine, in 92% of human BP [3]. During the first step of the splicing reaction the 2’OH of the BP adenosine attacks the first intronic nucleotide (nt) of the upstream 5’ss to form a lariat intermediate [4].

What identifies the branch point during RNA splicing?

During splicing, the branch point nucleotide initiates a nucleophilic attack on the 5′ donor splice site. The free end of the upstream intron then initiates a second nucleophilic attack on the 3′ acceptor splice site, releasing the intron as an RNA lariat and covalently combining the two exons (53).

Where is the branch site for splicing?

Within introns, a donor site (5′ end of the intron), a branch site (near the 3′ end of the intron) and an acceptor site (3′ end of the intron) are required for splicing. The splice donor site includes an almost invariant sequence GU at the 5′ end of the intron, within a larger, less highly conserved region.

Why is a branch point important?

Abstract. The branch point (BP) is one of the three obligatory signals required for pre-mRNA splicing. In mammals, the degeneracy of the motif combined with the lack of a large set of experimentally verified BPs complicates the task of modeling it in silico, and therefore of predicting the location of natural BPs.

How do I find my branch points?

The values of z that make the expression under the square root zero will be branch points; that is, z=±i are branch points. Let z−i=r1eiθ1 and z+i=r2eiθ2. Then f(z)=√z2+1=√r1r2ei(θ1+θ2)/2.

How are splice sites defined?

The location on a strand of messenger RNA where the molecule can be cut and reannealed during the regulation of protein synthesis by cells.

How do I check my branch points?

What is the order of a branch point?

In the case of an analytic function of several complex variables f(z), z=(z1… zn), n≥2, a point a of the space Cn or CPn is said to be a branch point of order m, 1≤m≤∞, if it is a branch point of order m of the, generally many-sheeted, domain of holomorphy of f(z).

What is branch point and branch line?

A branch line is a line extending out from a branch point defining a boundary between branches. When a variable z crosses a branch line the function f(z) switches from one branch to another. The heavy line OX in Fig. 1 extending from the branch point O to infinity is a branch line.

How do I find my branch point?

Are branch points singularities?

All branch points, by definition, are next to multiple valued points. A function therefore fails to be analytic at a branch point, meaning that all branch points are singularities.

What is an intronic mutation?

Definition. Deep intronic variants are those genetic variants falling more than 100bp away from the closest exon-intron boundary. Of course, like all other type of variants, deep intronic variants may be be pathogenic, but their pathogenicity is hard to be confirmed.

What is a consensus splice site?

The consensus 5′ splice site sequence is MAG/guragu and spans from the position −3 (the third nucleotide from the 3′ end of the upstream exon) to +6 (the sixth nucleotide in the intron). A score of 100 represents the best match to the consensus, whereas 0 is the worst.