Molec Bio CH. 14

What is the term for noncoding DNA that interrupts eukaryotic genes?

Introns

Which specific regions in a gene contain the sequences that finally appear in mature RNA?

Exons

Where do all RNA processing events occur before mRNA moves to the cytoplasm?

The nucleus

What is the process of cutting out introns and stitching together exons called?

RNA splicing

What two structures are added to the 5' and 3' ends of eukaryotic transcripts?

The cap and poly-A tail

In the first stage of splicing, what is the initial RNA molecule synthesized by RNA polymerase II called?

Primary transcript or Pre-mRNA

The 5' splice site is also known by what other name?

Donor site

Which highly conserved sequence is found at the beginning of an intron at the 5' splice site?

GU

Which snRNP recognizes the 5' splice site?

U1 snRNP

The 3' splice site is also known by what other name?

Acceptor site

Which highly conserved sequence marks the end of an intron at the 3' splice site?

AG

Which factor is responsible for recognizing the 3' splice site?

U2AF

In the two-step splicing model, what group on the adenosine nucleotide attacks the phosphodiester bond at the 5' splice site?

The 2'-OH group

What is the name of the looped structure formed by the intron during the splicing process?

Lariat

What specific invariant consensus sequence is found at the branchpoint in yeast?

UACUAAC

What is the large, dynamic ribonucleoprotein complex that catalyzes pre-mRNA splicing called?

Spliceosome

Name the three components found within a spliceosome.

Pre-mRNA, snRNPs, and splicing protein factors

What are the five snRNAs that can be resolved on a gel?

U1, U2, U4, U5, and U6

Which set of seven proteins is shared by all snRNPs?

Sm proteins

The binding of which snRNP to the 5' splice site marks the beginning of spliceosome assembly?

U1

The binding of U2 to the complex requires the input of what molecule?

ATP

Which three snRNPs join the complex to form the "B1 complex"?

U4, U5, and U6

Which snRNP must dissociate from U6 to allow the spliceosome to become active?

U4

During spliceosome activation, which snRNP displaces U1 at the 5' splice site?

U6

What process allows one gene to produce different protein products by choosing different combinations of exons?

Alternative splicing

What percentage of human genes are estimated to undergo alternative splicing?

Greater than 50%

What are the two types of self-splicing RNAs?

Group I and Group II

Which type of self-splicing reaction begins with an attack by a free guanine nucleotide?

Group I introns

In Group II self-splicing, what residue within the intron performs the intramolecular attack to form a lariat?

An A residue (adenosine)

Where are Group II introns typically found in bacteria?

In mRNA