ゲノム情報検索で解読した神経系遺伝子の出現と進化

Emergence and evolution of neuronal genes deciphered by genome informatics

Creators Kikuta Hiroki

Creators Araki Koji

Creators Aramaki Takahiro

Creators Kubo Yuga

Creators Tabata Natsuki

Creators Motozono Shogo

Creators Hoshida Hisashi

Creators Akada Rinji

Human neuronal proteins were searched to various animal genomes along with the phylogenetic tree using higher than 50% of query cover for the homology evaluation to know the presence or absence of homologs. Using the query cover value and gene ID of searched proteins, the number of homologous genes in the genomes was identified. The results showed that numbers of genes of synaptotagmin, neuronal channel proteins and myelin sheath proteins are increased along with evolution, implicating that these genes have roles in the development of neuronal network and neurotransmission. At the emergence of mammals, MEPE is appeared but missed only in egg-laying mammals. MEPE is a brain-specific protein negatively regulating bone mineralization. The emergence of MEPE is linked with the emergence of fetal animals. HTT gene of Huntington’s disease known as poly Q disease is appeared from lamprey, an ancestor of vertebrate. The lamprey HTT protein contains only one Q but the number of Q and also P existing next to poly Q in higher animals is dramatically increased and human has the longest poly Q-poly P sequence, suggesting that increase of the length of poly Q and P may have evolutionary role in brain development. The results of gene emergence and gene number transition in this study elucidated evolutional history of neuron and brain development.