Figure 1.

Isoforms of human brain tau. The region common to all isoforms is shown in blue, with the amino-terminal inserts encoded by exons 2 and 3 shown in red and green, respectively. The alternatively spliced repeat encoded by exon 10 is in yellow. The three or four tandem repeats are indicated by black bars. The tau isoforms range from 352 to 441 amino acids in length. Isoform A is expressed in fetal brain, whereas all six isoforms (A-F) are expressed in adult human brain. Transgenic mouse models based on the expression of isoform F 48 or isoform A 49 have been described.