title: Cephalopod eye evolution was modulated by the acquisition of Pax-6 splicing variants.
abstract: Previous studies have reported that the developmental processes of vertebrate eyes are controlled by four Pax-6 splicing variants, each modulating different downstream genes, whereas those of insect eyes are controlled by duplicated Pax-6 genes. Cephalopods belong to the Protostomes but possess a camera-type eye similar to those in vertebrates. We examined Pax-6 variations in the squid and found five types of Pax-6 splicing variants but no duplication of the Pax-6 gene. In the five splicing variants, the splicing patterns were produced by the combination of two additional exons to the ortholog and one jettisoned exon containing most of the Homeobox domain (HD). These five variants show spatio-temporal patterns of gene expression during development in the squid. Our study suggests that cephalopods acquired Pax-6 splicing variants independent of those in vertebrates and that these variants were similarly utilized in the development of the squid eye.
authors.affiliation: Research fellow of the Japan Society for the Promotion of Science, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Masa-aki
authors.initials: MA
authors.lastname: Yoshida
authors.affiliation: 1] Computational Biology, Graduate School of Humanities and Sciences [2] Center for Informational Biology, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo 112-8610, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Yura
authors.affiliation: Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, 526-0829, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ogura
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049830:Cephalopoda / Q000196:embryology / Q000235:genetics*; D005091:Exons; D005123:Eye / Q000196:embryology / Q000378:metabolism*; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics*; D007438:Introns; D008969:Molecular Sequence Data; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000737:chemistry / Q000235:genetics*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins