Inverted sequences in rat DNA

Polypyrimidine tracts isolated from inverted repeat sequences of rat DNA containing the repeat sequence d(CTC)

“…Looking for internal high repeat sequences of polypyrimidine tracts isolated from foldback DNA of the rat, we have analysed the distribution and the molar ratio of oligonucleotides obtained by RNase Ti digestion of complementary, polypurine RNA (cRNA(pur)). To avoid nearest-neighbour transfer of radioactivity from triphosphates labeled with 32P [7], we used ATP and GTP labeled with 3H. The size of cRNA transcribed from foldback DNA was 40-80 nucleotides, whereas the size of cRNA transcribed from polypyrimidine tracts was 50-200 nucleotides ( fig.1).…”

“…About 10' cpm of each 3H-labeled cRNA (transcribed either from polypyrimidine tracts or from foldback DNA) were digested with RNase Tr as in [7]. The oligonucleotides were separated in a two dimensional system: electrophoresis on cellulose acetate at pH 3.5, and thin-layer chromatography on cellulose impregnated with polyethyleneimine developed with pyridine-formate buffer (PH 3.5) [7]. The oligonucleotide spots were located by fluorography at -6doC and radioactivity of each spot was quantified in a scintillation counter.…”

S1nuclease definition of highly repeated DNA sequences in the Guinea pig, Cavia porcellus

“…The amount of snap-back DNA found in our sample, 2.7%, is in line with similar assays of three widely divergent DNAs. Analysis of Drosophila melanogaster (33), rat (34) and human (35) indicates that inverted repeats make up 3, 4 and 6% of these respective genomes. Allowing for these inverted repeat sequences, we find that the highly repeated sequences of the Guinea pig comprise 21% of the total DNA.…”

Professor Mieczysław Chorąży and His Works

“…In the 1970s research topics shifted to issues of cell ultrastructure, structure and function of nucleic acids, repetitive DNA sequences, and chromatin [12][13][14][15][16][17][18][19]. Later studies focused on the mechanisms of DNA transcription and changes in the activity of selected genes in regenerating rat liver and under heat shock conditions [20][21][22].…”