Info

sequence

(h)

Poly(A) tail

(d)

Transcription start site

(i)

5' cap

19. How would the deletion of the Shine-Dalgarno sequence affect a bacterial mRNA?

*20. How would the deletion of the following sequences or features most likely affect a eukaryotic pre-mRNA?

(a) AAUAAA consensus sequence

21. What would be the most likely effect on the amino acid sequence of a protein of a mutation that occurred in an intron of the gene encoding the protein? Explain your answer.

22. A geneticist induces a mutation in the gene that codes for cleavage and polyadenylation specificity factor (CPSF) in a line of cells growing in the laboratory. What would be the immediate effect of this mutation on RNA molecules in the cultured cells?

*23. A geneticist mutates the gene for proteins that bind to the poly(A) tail in a line of cells growing in the laboratory. What would be the immediate effect of this mutation in the cultured cells?

*24. An in vitro (within a test tube) splicing system has been developed that contains all the components (snRNAs, proteins, splicing factors) necessary for the splicing of nuclear pre-mRNA genes. When a piece of RNA containing an intron and two exons is added to the system, the intron is removed as a lariat and the exons are spliced together. What intermediate products of the splicing reaction would

0 0

Post a comment