title: Identification of a pentanucleotide telomeric sequence, (TTAGG)n, in the silkworm Bombyx mori and in other insects.
abstract: A pentanucleotide repetitive sequence, (TTAGG)n, has been isolated from a silkworm genomic library, using cross-hybridization with a (TTNGGG)5 sequence, which is conserved among most eukaryotic telomeres. Both fluorescent in situ hybridization and Bal 31 exonuclease experiments revealed major clusters of (TTAGG)n at the telomeres of all Bombyx chromosomes. To determine the evolutionary origin of this sequence, two types of telomeric sequence, (TTAGG)5 and a hexanucleotide repetitive sequence, (TTAGGG)4, which is conserved mainly among vertebrate and several invertebrate telomeres so far examined, were hybridized to DNAs from a wide variety of eukaryotic species under highly stringent hybridization conditions. The (TTAGGG)5 oligonucleotide hybridized to genomic DNAs from vertebrates and several nonvertebrate species, as has been reported so far, but not to any DNAs from insects. On the other hand, the Bombyx type of telomere sequence, (TTAGG)n, hybridized to DNAs from 8 of 11 orders of insect species tested but not to vertebrate DNAs, suggesting that this TTAGG repetitive sequence is conserved widely among insects.
authors.affiliation: Zoological Institute, Faculty of Science, University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Okazaki
authors.forename: K
authors.initials: K
authors.lastname: Tsuchida
authors.forename: H
authors.initials: H
authors.lastname: Maekawa
authors.forename: H
authors.initials: H
authors.lastname: Ishikawa
authors.forename: H
authors.initials: H
authors.lastname: Fujiwara
mesh_terms: D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics*; D002875:Chromosomes / Q000648:ultrastructure*; D017124:Conserved Sequence; D003429:Cross Reactions; D004706:Endodeoxyribonucleases / Q000378:metabolism; D005057:Eukaryotic Cells; D015723:Gene Library; D017403:In Situ Hybridization; D007313:Insecta / Q000235:genetics; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics*; D010802:Phylogeny; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D013045:Species Specificity; D016615:Telomere; D014018:Tissue Distribution
chemical_list: D009841:Oligonucleotides; D004706:Endodeoxyribonucleases; C038407:exonuclease Bal 31