Fig. 2.

Known TTN isoforms and TTN splicing patterns at the I-band, Z-band, and M-band. a Known TTN isoforms in striated muscles. b Nine Ig domains with insertions in the Z-band and overview of the Z-repeat isoforms expressed in different types of striated muscles. The repeats Zr1, 2, 3, and 7 express in all striated muscles, whereas Zr4, 5, and 6 are alternatively spliced, depending on the tissue type and the developmental stage. c Alternative splicing of the M-band. The right panel shows the approximate ratio of Mex5+:Mex5− in striated muscles. E, exon; Z, Ig domain repeats; Zr, Z-repeats between Z3 and Z4; Mex, M-band exon