title: AT-rich linkers in long range organisation of Drosophila DNA.
abstract: AT-rich segments were mapped in 6 different domains of the Drosophila melanogaster genome by partial denaturation of cloned genomic DNA segments and observation in the electron microscope (EM). As found in a previous investigation (Moreau et al., 1982), three types of AT-rich segments could be distinguished: 1) AT-rich linkers with a very high AT content, 600 +/- 200 bp long; 2) clusters of such AT-linkers extending over up to 10 Kbp and 3) AT-rich stretches which are shorter and of lower AT content compared to AT-linkers. Six genes previously localized in these domains were found to lie in relatively GC-rich segments framed by AT-rich elements of the 3 types: the Larval Serum Protein LSP-1 alpha gene is framed by 2 AT-linkers, the LSP-1 beta and LSP-2 genes by two AT-rich stretches, an the LSP-1 gamma gene by a cluster and a stretch. The 55 Kbp genomic segment encompassing the P6 gene contains and AT-cluster of about 15 Kbp and several AT-linkers and AT-rich stretches. The 85 Kbp domain containing the P1 gene includes 3 AT-rich clusters of about 10 Kbp each framing GC-rich domains punctuated by AT-linkers and stretches. This study shows that AT-mapping allows a rapid diagnosis of large genomic DNA domains in relation to the AT-rich segments which, possibly, are of significance with regard to genome organisation and function.
authors.forename: J
authors.initials: J
authors.lastname: Moreau
authors.forename: J
authors.initials: J
authors.lastname: Kejzlarova-Lepesant
authors.forename: H
authors.initials: H
authors.lastname: Brock
authors.forename: J A
authors.initials: JA
authors.lastname: Lepesant
authors.forename: K
authors.initials: K
authors.lastname: Scherrer
mesh_terms: D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000648:ultrastructure; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis*; D004262:DNA Restriction Enzymes; D004331:Drosophila melanogaster / Q000235:genetics*; D005559:Formamides; D005796:Genes; D008854:Microscopy, Electron; D008970:Molecular Weight; D009691:Nucleic Acid Denaturation; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D005559:Formamides; D012333:RNA, Messenger; C031066:formamide; D004247:DNA; D004262:DNA Restriction Enzymes