Biomaterial Database

Replication in Drosophila chromosomes. I. Replication of intranucleolar DNA in polytene cells of D. nasuta. 1979

S C Lakhotia, and S Roy

The organization and replication of intranucleolar DNA in polytene cells of Drosophila nasuta have been examined. Normal Giemsa and fluorescent (Hoechst 33258 and quinacrine mustard) staining reveal that in D. nasuta polytene cells, the intranucleolar DNA is organized into condensed and disperse forms and very often shows connexion to the alpha heterochromatin of the chromocentre. Results of [3H]thymidine autoradiography indicate that the known underreplication of rDNA sequences in polytene cells is due to the slower replication of the intranucleolar DNA. Some aspects of the organization of condensed and disperse intranucleolar DNA are discussed.

UI	MeSH Term	Description	Entries
D002466	Cell Nucleolus	Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)	Plasmosome,Cell Nucleoli,Nucleoli, Cell,Nucleolus, Cell,Plasmosomes
D002875	Chromosomes	In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Chromosome
D004261	DNA Replication	The process by which a DNA molecule is duplicated.	Autonomous Replication,Replication, Autonomous,Autonomous Replications,DNA Replications,Replication, DNA,Replications, Autonomous,Replications, DNA
D004330	Drosophila	A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.	Fruit Fly, Drosophila,Drosophila Fruit Flies,Drosophila Fruit Fly,Drosophilas,Flies, Drosophila Fruit,Fly, Drosophila Fruit,Fruit Flies, Drosophila
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013936	Thymidine	A nucleoside in which THYMINE is linked to DEOXYRIBOSE.	2'-Deoxythymidine,Deoxythymidine,2' Deoxythymidine