The DNA sequence of 168 promoter regions (-50 to +10) for Escherichia coli RNA polymerase were compiled. The complete listing was divided into two groups depending upon whether or not the promoter had been defined by genetic (promoter mutations) or biochemical (5' end determination) criteria. A consensus promoter sequence based on homologies among 112 well-defined promoters was determined that was in substantial agreement with previous compilations. In addition, we have tabulated 98 promoter mutations. Nearly all of the altered base pairs in the mutants conform to the following general rule: down-mutations decrease homology and up-mutations increase homology to the consensus sequence.

/pdf/compilation-and-analysis-of-escherichia-coli-promoter-dna-3laukojglx.pdf

Compilation and analysis of Escherichia coli promoter DNA sequences.

In gel electrophoresis, nucleic acids and protein-detergent complexes larger than a threshold size all migrate at the same rate. For DNA molecules, this effect can be overcome by the simple procedure of periodically inverting the electric field. Tuning the frequency of the field inversions from 10 to 0.01 hertz, makes it possible to resolve selectively DNA's in the size range 15 to greater than 700 kilobase pairs.

https://science.sciencemag.org/content/sci/232/4746/65.full.pdf

Electrophoretic separations of large DNA molecules by periodic inversion of the electric field

Malaria parasites are haploid for most of their life cycle, with zygote formation and meiosis occurring during the mosquito phase of development. The parasites can be analyzed genetically by transmitting mixtures of cloned parasites through mosquitoes to permit cross-fertilization of gametes to occur. A cross was made between two clones of Plasmodium falciparum differing in enzymes, drug sensitivity, antigens, and chromosome patterns. Parasites showing recombination between the parent clone markers were detected at a high frequency. Novel forms of certain chromosomes, detected by pulsed-field gradient gel electrophoresis, were produced readily, showing that extensive rearrangements occur in the parasite genome after cross-fertilization. Since patients are frequently infected with mixtures of genetically distinct parasites, mosquito transmission is likely to provide the principal mechanisms for generating parasites with novel genotypes.

https://science.sciencemag.org/content/sci/236/4809/1661.full.pdf

Genetic analysis of the human malaria parasite plasmodium falciparum

The Apicomplexa are a phylum of diverse obligate intracellular parasites including Plasmodium spp., the cause of malaria; Toxoplasma gondii and Cryptosporidium parvum, opportunistic pathogens of immunocompromised individuals; and Eimeria spp. and Theileria spp., parasites of considerable agricultural importance. These protozoan parasites share distinctive morphological features, cytoskeletal organization, and modes of replication, motility, and invasion. This review summarizes our current understanding of the cytoskeletal elements, the properties of cytoskeletal proteins, and the role of the cytoskeleton in polarity, motility, invasion, and replication. We discuss the unusual properties of actin and myosin in the Apicomplexa, the highly stereotyped microtubule populations in apicomplexans, and a network of recently discovered novel intermediate filament-like elements in these parasites.

/pdf/cytoskeleton-of-apicomplexan-parasites-1b480mrwg1.pdf

Cytoskeleton of Apicomplexan Parasites

Allelic dimorphism in a surface antigen gene of the malaria parasite Plasmodium falciparum.

At least seven chromosome-sized DNA molecules (750 to 2000 kilobases in length and one fraction of undetermined molecular weight) from cultured clones and isolates of Plasmodium falciparum have been separated by pulsed-field gradient gel electrophoresis Whereas asexual blood stages and sexual stages of the same line have identical molecular karyotypes, the length of chromosome-sized DNA molecules among different geographical isolates and several clones derived from a single patient is different These length alterations of chromosomes are the result of DNA rearrangements that must occur unrelated to sexual differentiation

https://science.sciencemag.org/content/sci/229/4714/658.full.pdf

Chromosome-sized DNA molecules of Plasmodium falciparum

Extremely diverged actin proteins in Plasmodium falciparum.

Hybridization studies have indicated that on the M13 genome there are located regions which are transcribed in vivo with a high as well as with a low frequency. The region with the highest transcriptional activity coincides with the region coding for the polypeptides which during the infection cycle are needed most abundantly (gene V and gene VIII protein). The hybridization studies furthermore have indicated that at least a number of the promoters previously detected in vitro are operative in the infected cell. In addition the experimental data are consistent with the presence of three transcription termination signals on the M13 genome.



With the aid of analytical and preparative hybridization studies we have been able to establish that during the infection cycle at least eleven M13-specific RNA species are made which range in size from 280 to 2000 nucleotides. The six major RNA species (i.e. an 8-S RNA with 370 nucleotides, a 9-S with 420, three 11-S species with 760, 810 and 860 nucleotides and a 14-S species with 1140 nucleotides) are encoded by the region with the highest transcriptional activity (located between the N-terminal end of gene X and the C-terminal end of gene VIII). Characterization of these RNA species with respect to their genetic origin, codogenic properties and nucleotide sequences has indicated that their synthesis is terminated at the previously detected rho-independent transcription termination signal T0.25, which is located immediately after gene VIII. From the data obtained it furthermore could be deduced that the 5′ termini of these RNA species are located as follows: for the 8-S RNA immediately in front of gene IX (promoter G0.18), the 9-S RNA within or immediately distal to the 5′ end of gene VII, the three 11-S RNAs within the C-terminal end of gene X and the 14-S RNA immediately in front of gene X. Analyses of the 5′ ends of the major RNA chains synthesized in vivo have indicated that four (i.e. the 9-S and three 11-S species) out of the six RNA species are the result of processing of precursor molecules. For this processing the RNA processing enzymes RNase III, RNase E, and RNase P are not required. The meaning of these results, in terms of the mechanisms by which the expression of the M13 genome is regulated, is discussed.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1980.tb07206.x

Expression of Bacteriophage M13 DNA in vivo

During the infection cycle of the filamentous bacteriophage M13 a phage specific RNA species is made which selectively directs in vitro the synthesis of the precursor of the major capsid protein encoded by gene VIII. This RNA is unstable (its mean half-life is 11 min) and is made in amounts representing at least 2% of the newly synthesized RN. Nucleotide sequence analysis have indicated that the synthesis of this RNA species is initiated and terminated at the same promoter (G0.18) and termination signal (T0.25) of the M13 genome as the 8S RNA species made in vitro under the direction of M13 replicative form DNA.

Expression of bacteriophage M13 DNA in vivo. Localization of the transcription initiation and termination signal of the mRNA coding for the major capsid protein

Mari A. Smits

Papers

Chromosome-sized DNA molecules of Plasmodium falciparum

Extremely diverged actin proteins in Plasmodium falciparum.

Expression of Bacteriophage M13 DNA in vivo

Expression of bacteriophage M13 DNA in vivo. Localization of the transcription initiation and termination signal of the mRNA coding for the major capsid protein

Expression of bacteriophage M13 DNA in vivo: I. Synthesis of phage-specific RNA and protein in minicells