Absence of complete repression of a specific part of the DNA during in vitro transcription of yeast deoxyribonucleoprotein

Abstract

A deoxyribonucleoprotein isolated from Saccharomyces cerevisiae was used as a template for the in vitro synthesis of RNA with Escherichia coli RNA polymerase. No significant differences between the base composition of this RNA and RNA synthesized with DNA as template could be detected. The RNA's synthesized with DNA or deoxyribonucleoprotein both hybridize with DNA to the same extent. On extrapolation to an infinite RNA concentration it appears that 42–45 % of the DNA can be saturated. Self-annealing experiments show that at least 60 % of both kinds of RNA were self-complementary, indicating a high degree of symmetric transcription. No differences between the two kinds of RNA were observed when they were used in competition hybridization to compete for a natural RNA fraction, or for RNA transcribed from DNA.

From the resemblance in base composition and hybridization properties between RNA synthesized with DNA or deoxyribonucleoprotein as template it is concluded that permanent repression of a large part of the DNA in yeast deoxyribonucleoprotein is absent.