Biomaterial Database

Inversion of 5S ribosomal RNA genes within the genus Coprinus. 1987

J R Cassidy, and P J Pukkila

Department of Biology, University of North Carolina, Chapel Hill 27514.

In the basidiomycete fungus Coprinus cinereus, the 5S ribosomal RNA (rRNA) genes are found in the rDNA repeat which encodes the other three rRNAs (18S, 5.8S, and 26S), and all genes are transcribed in the same direction (Cassidy et al. 1984). To facilitate examination of the rRNA gene organization in additional species, we developed a method to permit determination of the direction of transcription of the rRNA genes using crude preparations of genomic DNA. We used this method to determine the organization of the rDNA in five other members of the order Agaricales (Flammulina velutipes, Agaricus bisporus, Coprinus micaceus, Coprinus atramentarius, and Coprinus comatus). In four, the organization is the same as it is in Coprinus cinereus. However, in Coprinus comatus, the 5S RNA gene is present in the rDNA repeat, but is transcribed in the opposite direction. This alteration in rDNA organization within the genus Coprinus indicates that inverted 5S genes can arise and become propagated through the tandem array of genes. The presence of orientation-dependent promoter elements within the spacer DNA (Elion and Warner 1984) would be expected to place constraints on such inversions.

UI	MeSH Term	Description	Entries
D007446	Chromosome Inversion	An aberration in which a chromosomal segment is deleted and reinserted in the same place but turned 180 degrees from its original orientation, so that the gene sequence for the segment is reversed with respect to that of the rest of the chromosome.	Inversion, Chromosome,Inversion, Chromosomal,Chromosomal Inversion,Chromosomal Inversions,Chromosome Inversions,Inversions, Chromosomal,Inversions, Chromosome
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D003302	Coprinus	A genus of black-spored basidiomycetous fungi of the family Coprinaceae, order Agaricales; some species are edible.
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, DNA
D004271	DNA, Fungal	Deoxyribonucleic acid that makes up the genetic material of fungi.	Fungal DNA
D005800	Genes, Fungal	The functional hereditary units of FUNGI.	Fungal Genes,Fungal Gene,Gene, Fungal
D000363	Agaricales	An extensive order of basidiomycetous fungi whose fruiting bodies are commonly called mushrooms.	Agaricaceae,Mushrooms,Agaricale,Mushroom
D012335	RNA, Ribosomal	The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)	Ribosomal RNA,15S RNA,RNA, 15S
D012341	RNA, Ribosomal, 5S	Constituent of the 50S subunit of prokaryotic ribosomes containing about 120 nucleotides and 34 proteins. It is also a constituent of the 60S subunit of eukaryotic ribosomes. 5S rRNA is involved in initiation of polypeptide synthesis.	5S Ribosomal RNA,5S rRNA,RNA, 5S Ribosomal,Ribosomal RNA, 5S,rRNA, 5S
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species