title: Evidence for rolling circle replication of tandem genes in Drosophila.
abstract: Extrachromosomal circular DNA (eccDNA) is one characteristic of the plasticity of the eukaryotic genome. It is found in various organisms and contains sequences derived primarily from repetitive chromosomal DNA. Using 2D gel electrophoresis, we have previously detected eccDNA composed of chromosomal tandem repeats throughout the life cycle of Drosophila. Here, we report for the first time evidence suggesting the occurrence of rolling circle replication of eccDNA in Drosophila. We show, on 2D gels, specific structures that can be enriched by benzoylated naphthoylated DEAE-cellulose chromatography and were identified in other systems as rolling circle intermediates (RCIs). These RCIs are homologous to histone genes, Stellate and Suppressor of Stellate, which are all organized in the chromosomes as tandem repeats. RCIs are detected throughout the life cycle of Drosophila and in cultured fly cells. These structures are found regardless of the expression of the replicated gene or of its chromosomal copy number.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Tel-Aviv University Tel Aviv 69978, Israel. scohen@post.tau.ac.il
authors.forename: Sarit
authors.initials: S
authors.lastname: Cohen
authors.forename: Neta
authors.initials: N
authors.lastname: Agmon
authors.forename: Keren
authors.initials: K
authors.lastname: Yacobi
authors.forename: Margarita
authors.initials: M
authors.lastname: Mislovati
authors.forename: Daniel
authors.initials: D
authors.lastname: Segal
mesh_terms: D000818:Animals; D002848:Chromatography, DEAE-Cellulose; D004261:DNA Replication; D004270:DNA, Circular / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D015870:Gene Expression; D017344:Genes, Insect; D006657:Histones / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics; D008297:Male; D011494:Protein Kinases / Q000235:genetics; D020080:Tandem Repeat Sequences
chemical_list: D004270:DNA, Circular; D029721:Drosophila Proteins; D006657:Histones; D019476:Insect Proteins; D011494:Protein Kinases; C094331:Ste protein, Drosophila