TAp63 proteins contain an
N-terminal TA domain that is 22 % homologous to that of
p53, while ΔNp63 isoforms are transcribed from an alternative
promoter within the third intron and thus bear no
resemblance to the p53 TAD. Instead, the fourth exon,
denominated exon 3’, encoding the N-terminus in ΔNp63
proteins, is spliced out in TAp63 transcripts. The 14 unique N-terminal amino acid residues in ΔNp63 isoforms have
been shown to possess transactivation activity,thus
making ΔNp63 proteins bona fide transcription factors.
Additional alternative splicing yields five different Ctemini,
α, β, γ, δ, and ε, for a total of ten different isoforms