Fig. 6

Saitohin (STH) gene locus in MAPT 5’intron 11. a Genomic repetitive element distribution in human MAPT intron 11 showing overlap of the saitohin main ORF with an L2c LINE2 element and an LTR1 long terminal repeat element predicted by REPEATMASKER (http://www.repeatmasker.org/). b An expanded view of the saitohin main ORF designated exon 4 here, overlapping with L2c and LTR1 elements within MAPT 5’intron 11, together with discontiguous, putative exons 1–3 and 5 encoding possible N- and C-terminal extensions. c Saitohin extended amino acid graphic alignment by TBLASTN for the 22 primate genomes listed. d A saitohin full-length pHMM reflects the relative conservation of individual amino acids as their probable frequency (letter size) while the information content or functional potential is reflected in total column height, exemplified by the conserved RGE motif marked in red highlight. This recognized exon 4 ORF is complete only for 7 Catarrhine apes, while N- or C-terminal ORF extensions with an upstream Met or downstream Stop codon have been observed for Macaca fascicularis, Papio anubis and Pongo abelii. Missense or nonsense mutations disrupt the main ORF in various species, although recent RNA Seq data may rectify the true genomic sequences to yield a longer translated protein in some cases (see text). e Saitohin protein 3D model (242 aa) predicted by I-TASSER with the confirmed single exon 4 ORF highlighted in blue, the disease-associated SNP “Q7R” at position 89 and an exposed RGE motif at positions 200–202