Organization of the ribosomal RNA genes of dictyostelium discoideum: Mapping of the nontrascribed spacer regions

  title={Organization of the ribosomal RNA genes of dictyostelium discoideum: Mapping of the nontrascribed spacer regions},
  author={A. Cockburn and M. J. Newkirk and R. Firtel},
Most of the Dictyostelium ribosomal nontranscribed spacer DNA has been mapped using Eco R1, Hind III, and Sal I restriction digests and recombinant plasmids containing parts of the rDNA (ribosomal DNA). The repeat units are at least 42 kb (1 kilobase = 1000 base pairs = 1 kb) long; of this, 8 kb codes for the 36S rRNA precursor. The repeat units give a homogeneous pattern of Sal I, Eco R1, and Hind III restriction fragments. The repeats could be linked by a heterogeneous region in the… Expand
Sequence and structure of the extrachromosomal palindrome encoding the ribosomal RNA genes in Dictyostelium.
By interrogating a library of ordered YAC clones, this work provides evidence for a chromosomal copy of the rDNA on chromosome 4, and suggests that this locus may provide master copies for the stable transmission of the extrachromosomal elements. Expand
Renaturation kinetics indicate that the actin mRNA complementary region is reiterated approximately 15–20 times in the Dictyostelium genome. Expand
Identification and mapping of a 60 bp EcoRI fragment in the Dictyostelium discoideum ribosomal DNA.
The organization of the transcribed sequences in the ribosomal DNA repeat unit of Dictyostelium discoideum is re-examined and a fifth fragment which defines a small portion of the 25S ribosome RNA is identified and cloned. Expand
Chromatin structure along the ribosomal DNA of Dictyostelium. Regional differences and changes accompanying cell differentiation.
The combined results suggest that whereas regions that are not transcribed are packaged with proteins that protect them from nuclease digestion, actively transcribing ribosomal genes are associated with few macromolecular constituents apart from those required for transcription and its regulation. Expand
An irregular satellite sequence is found at the termini of the linear extrachromosomal rDNA in Dictyostelium discoideum
It is shown that virtually all the rDNA in Dictyostelium exists in the linear palindromic form, and that the heterogeneity can be accounted for by variable tracts of an unprecedented irregular satellite sequence with the general formula [CnT]m. Expand
Ribosomal DNA of the fly Sciara coprophila has a very small and homogeneous repeat unit
It is shown that the unit repeat of the fly Sciara coprophila is only 8.4 kb which is the smallest known for a multicellular eukaryote, and that virtually all gene copies are actively being transcribed in the stage of spermatogenesis examined, the first demonstration for any reiterated gene family where all copies are shown to be simultaneously active. Expand
Dictyostelium rDNA consists of non-chromosomal palindromic dimers containing 5S and 36S coding regions
Analysis of the mobility of total cell DNA in 0.15% agarose gels indicates that the majority of the rDNA is not covalently attached to chromosomal DNA. Expand
Zea mays chloroplast ribosomal RNA genes are part of a 22,000 base pair inverted repeat
Zea mays chloroplast rDNA exists in two identical units. Each unit contains one sequence for the 16, 23 and 5S rRNAs in the order given. The 16 and 23S sequences in each unit are separated by a 2100Expand
Sequence and Generation of Mature Ribosomal RNA Transcripts in Dictyostelium discoideum
A model for the maturation of the rRNAs in Dictyostelium discoideum is proposed that is compared with the processing ofThe rRNA transcription unit of Saccharomyces cerevisiae. Expand
Identification and analysis of Dictyostelium actin genes, a family of moderately repeated genes
The results suggest that there are at least two different functional genes, and possibly more, for Dictyostelium actin. Expand


Structural organization of the genome of Dictyostelium discoideum: analysis by EcoR1 restriction endonuclease.
The genome of the cellular slime mold Dictyostelium discoideum has been analyzed by limit digestion with Eco R1 restriction endonuclease and analysis by renaturation kinetics indicates that it is repeated approximately 200 times per haploid genome and that it was not internally repeated. Expand
The isolation of RNA homologous to the genetic control elements of the lactose operon.
A sequential DNA-RNA hybridization procedure is described whereby RNA homologous to a target DNA region 35 to 140 base pairs in length can be purified up to 6700-fold from a complex in vitroExpand
A system for mapping DNA sequences in the chromosomes of Drosophila melanogaster.
Individual segments of the chromosomal DNA in D. melanogaster were isolated, and the sequences they contain were analyzed for repetition and mapped within the polytene chromosomes, which are not compatible with tandem repetition models for the chromomere. Expand
Enzymatic end-to end joining of DNA molecules.
Abstract A way to join naturally occurring DNA molecules, independent of their base sequence, is proposed, based upon the presumed ability of the calf thymus enzyme terminalExpand
Effect of Growth Conditions on the Formation of the Relaxation Complex of Supercoiled ColE1 Deoxyribonucleic Acid and Protein in Escherichia coli
Inhibition of protein synthesis in log cultures by the addition of chloramphenicol or amino acid starvation allows ColE1 DNA to continue replicating long after chromosomal replication has ceased. Expand
Detection of specific sequences among DNA fragments separated by gel electrophoresis.
  • E. Southern
  • Biology, Medicine
  • Journal of molecular biology
  • 1975
This paper describes a method of transferring fragments of DNA from agarose gels to cellulose nitrate filters. The fragments can then be hybridized to radioactive RNA and hybrids detected byExpand