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Genetic information 'created' by archaebacterial DNA polymerase.

ABSTRACT: DNA polymerase catalyses replication of cellular DNA. The reaction requires a primer-template complex, and a new DNA chain grows from the 3' end of the primer along the template; no genetic information is created in this reaction. We demonstrate that DNA polymerase from Thermococcus litoralis, a hyperthermophilic marine Archaea, can synthesize up to 50000 bp of linear double-stranded DNA in the complete absence of a primer-template complex, indicating that genetic information is 'created.' The possibility of DNA contamination in the reaction mixture, which may serve as a primer and/or template, was vigorously excluded; for example, pretreatment of DNA polymerase with DNase I or extensive chromatographic purification of the substrate, deoxyribonucleoside 5'-triphosphates, did not abolish the primer-template-independent DNA synthesis. The DNA synthesized was (CTAGATAT)n, (TAGATATCTATC)n or a related sequence. Similar repetitive sequences are found in centromeric satellite DNA of many organisms. The significance of this ab initio DNA synthesis is that genetic information can flow from protein to DNA.

SUBMITTER: Ogata N

PROVIDER: S-EPMC1218480 | biostudies-other | 1997 Jun

REPOSITORIES: biostudies-other

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Creation of genetic information by DNA polymerase of the thermophilic bacterium Thermus thermophilus.

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Creation of genetic information by DNA polymerase of the archaeon Thermococcus litoralis: influences of temperature and ionic strength.

Project description:DNA polymerase of the archaeon Thermococcus litoralis can synthesize a long stretch of linear double-stranded DNA in the complete absence of added primer and template DNAs. This finding suggests that genetic information can potentially be created by protein. We report here the effects of temperature, ionic strength and pH on this ab initio DNA synthesis by the protein in vitro . When the temperature of the reaction was changed, the sequence of the product DNA changed markedly. For instance, the reaction products were (TAAT) n at 69 degrees C, (TATCCGGA) n at 84 degrees C and (TATCGCGATAGCGATCGC) n at 89 degrees C. The ionic strength of the reaction condition also affected the sequence: it was (TATCTAGA) n with 0 mM KCl, (TATATACG) n with 50 mM KCl and (TATAGTTATAAC) n with 100 mM KCl at 74 degrees C. When the pH of the reaction condition was changed from 6.8 to 10.8, the size of the product DNA decreased, but its sequence did not. These results demonstrate that DNA synthesized ab initio by DNA polymerase of T.litoralis is markedly influenced by the reaction conditions. The results also suggest that genetic information that might have been created by protein on the early earth is strongly influenced by environmental factors.

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