Genetics: Analysis and Principles 5th Edition by Robert Brooker

Exercise 8

Figure 16.8 shows the products of alternative splicing for the -tropomyosin pre-mRNA. Let's suppose that smooth muscle cells produce splicing factors that are not produced in other cell types. Explain where you think such splicing factors bind and how they influence the splicing of the -tropomyosin pre-mRNA.FIGURE 16.8 Alternative ways that the rat -tropomyosin pre-mRNA can be spliced. The top part of this figure depicts the structure of the rat -tropomyosin pre-mRNA. Exons are shown as colored boxes, and introns are illustrated as connecting black lines. The lower part of the figure depicts the mature mRNA of smooth and striated muscle cells. The constitutive exons (red) are found in the mature -tropomyosin mRNAs in all cell types. Alternative exons are also found in mRNAs but they vary from one cell type to another. Though exon 8 in this figure is found in both mature mRNAs, it is considered an alternative exon because it is not found in the mature -tropomyosin mRNAs of some other cell types.