Complex patterns of eukaryotic mRNA splicing

The pre-mRNA transcript of the rat α-tropomyosin gene is alternatively spliced in different cell types. The light green boxes represent introns; the other colors represent exons. Polyadenylation signals are indicated by an A. Dashed lines in the mature mRNAs indicate regions that have been removed by splicing. TM = tropomyosin.

[Data from J. P. Lees et al., Mol. Cell. Biol. 10, 1990, 1729-1742.]