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Repetitive DNA in Escherichia coli: multiple sequences complementary to small stable RNAs
1Department of Microbiology and Immunology, Washington University, School of Medicine, St. Louis, Missouri 63110.
Molecular & General Genetics : MGG
|January 1, 1979
Summary
Radioactively labeled RNA molecules from Escherichia coli bind to multiple DNA fragments. Analysis indicates these DNA sequences are reiterated and non-adjacent within the E. coli genome.
Area of Science:
- Molecular Biology
- Genomics
- Microbiology
Background:
- Escherichia coli (E. coli) is a model organism for studying bacterial genetics.
- Understanding the organization of the E. coli genome is crucial for deciphering gene regulation and function.
- RNA molecules play diverse roles in gene expression and cellular processes.
Purpose of the Study:
- To investigate the genomic location and organization of specific RNA molecules in Escherichia coli.
- To determine if the DNA sequences corresponding to these RNAs are unique or repeated within the genome.
- To analyze the arrangement of these reiterated sequences.
Main Methods:
- Hybridization of radioactively labeled 4.5S, 6S, and 10S RNAs to EcoRI-digested E. coli genomic DNA fragments.
- Analysis of renaturation kinetics using Cot curve analysis to study the annealing of RNAs to denatured DNA.
Main Results:
- Each of the studied RNA molecules hybridized to multiple EcoRI DNA fragments, indicating binding to more than one genomic location.
- Cot curve analysis revealed that the DNA sequences corresponding to these RNAs are reiterated within the E. coli genome.
- The reiterated sequences were found to be non-adjacent in their genomic organization.
Conclusions:
- The DNA sequences encoding 4.5S, 6S, and 10S RNAs in E. coli are present in multiple copies.
- These repeated DNA sequences are distributed non-adjacently throughout the E. coli genome.
- This suggests a complex genomic organization for these specific RNA molecules.