title: The organisation of genes for transfer RNA and ribosomal RNA in amoebae and plasmodia of Physarum polycephalum.
abstract: 1. Using hybridisation techniques nuclei from both amoebae and plasmodia of Physarum polycephalum were found to contain 275 genes each coding for 5.8-S, 19-S and 26-S rRNA, 685 genes for 5-S rRNA and 1050 genes for tRNA. 2. Hybridisation of these RNA species to both amoebal and plasmodial DNA fractionated on CsCl gradients reveal that the 5.8-S, 19-S and 26-S rRNA genes are located at a satellite position (formula: see text) with respect to the main band of DNA, whereas 4-S RNA genes are located exclusively in the main band of DNA (formula: see text). 3. This result was confirmed by demonstrating that only the 5.8-S, 19-S and 26-S rRNA species hybridise to purified plasmodial ribosomal DNA. 4. The 19-S and 26-S rRNA genes of amoebae are located on extrachromosomal DNA molecules of a discrete size (Mr = 38 X 10(6)) with identical properties to plasmodial ribosomal DNA.
mesh_terms: D002467:Cell Nucleus / Q000032:analysis; D004247:DNA / Q000302:isolation & purification / Q000378:metabolism; D005111:Extrachromosomal Inheritance; D005796:Genes; D005815:Genetic Code; D009235:Myxomycetes / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D010804:Physarum / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*
chemical_list: D012335:RNA, Ribosomal; D004247:DNA; D012343:RNA, Transfer