#Question id: 4076
#Unit 3. Fundamental Processes
RNA-binding proteins
a. can be identified by chromatography of UV irradiated nuclear extracts over oligo-dT columns.
b. can be identified by sequence homology to known RNA-binding domains.
c. have a conserved structure as seen by X-ray crystallographic analysis.
d. alter the secondary structure of pre-mRNAs, which decreases interactions with other RNAs or proteins.
e. always remain in the nucleus.
#Question id: 4077
#Unit 3. Fundamental Processes
Which of the following is (are) associated with most polyadenylation events?
a. cleavage of the 5ยด end of the RNA molecule
b. an assembly of a large, multiprotein complex
c. the AAUAAA site upstream of where polyadenylation will occur
d. a GU-rich or U-rich region near the cleavage site
e. slow addition of A residues followed by rapid addition of 200 to 250 more A residues
#Question id: 4078
#Unit 3. Fundamental Processes
Which of the following is (are) required for splicing to occur?
a. two transesterification reactions
b. intact, naturally occurring introns
c. formation of a lariat like structure
d. a branch-point G residue
#Question id: 4079
#Unit 3. Fundamental Processes
What is the evidence that pre-mRNAs are not synthesized unless machinery for processing is properly positioned?
#Question id: 4080
#Unit 3. Fundamental Processes
How the location of exons and introns within a gene are determined?
#Question id: 4081
#Unit 3. Fundamental Processes
Which of the following regulatory scenarios of cell-type-specific expression of fibronectin isoforms in humans is (are) consistent with information on known splicing factors?
a. A Tra-like splicing factor expressed in fibroblasts is required for inclusion of EIIIA and EIIIB exons.
b. An Sxl-like splicing factor is required in hepatocytes for exclusion of EIIIA and EIIIB exons.
c. A Tra-2-like factor enhances binding of the cleavage/polyadenylation complex in fibroblasts.
d. A Dsx-like protein is required to inhibit transcription of the fibronectin gene.