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Nucleic Acids Res September 1, 1976; 3 (9): 2367-77.

The presence of (dA.dT)20-25 tracts in the DNA of primitive eukaryotes.

Mol JN , Flavell RA , Borst P .

Previous work by Jacobson et al. (1) has shown that the number and distribution of (dA.dT)25 tracts in the nuclear DNA of the slime mold Dictyostelium discoideum reflects the number and the distribution of transcriptional units. To investigate whether this is a general phenomenon we compared the nuclear DNAs of other primitive eukaryotes with respect to their content of large (dA.dT)n tracts via the thermal stability of their hybrids with poly(rA). The results of our analysis indicate that all nuclear DNAs tested have (dA.dT)20-25 tracts, but the frequency of such tracts varies from one per 5.4 X 10(6) daltons in Dictyostelium nuclear DNA to one per 2.8 X 10(8) daltons in Crithidia luciliae nuclear DNA. We conclude that the presence of (dA.dT)20-25 tracts is not an obligatory characteristic of the transcriptional unit in primitive eukaryotes. Chromatography of native DNAs on poly(rU) Sephadex columns shows that the large (dA.dT)n tracts occurring in the genomes of both primitive and higher eukaryotes are widely distributed throught these genomes.

PubMed ID: 823532
PMC ID: PMC343091
Article link: Nucleic Acids Res

Species referenced: Xenopus
Genes referenced: tbx2

References [+] :
Birnboim, Analysis of long pyrimidine polynucleotides in HeLa cell nuclear DNA: absence of polydeoxythymidylate. 1974, Pubmed