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C Tribioli

Publications and source records attributed to C Tribioli.

21 records · Page 2Linked to original sources

Characterization of human DNA sequences synthesized at the onset of S-phase.

We developed a method of enrichment for DNA replicated at the onset of S-phase in synchronized human HL60 cells. About 200 such sequences were cloned. The analysis of this selected DNA sample showed that: 1) the cloned DNA fragments derive from a limited number (750-1500) of replicons; 2) there is no extensive homology between different DNA fragments; 3) they are not significantly enriched in highly repeated sequences; 4) they are enriched in snap-back (Cot = o) DNA. The sequence of the longest fragment revealed the presence of numerous signals collected in a few hundred nucleotides: 1) homology with the origin of replication of human Papovaviruses usually associated with potential stem-loop structures; 2) binding sites for known transcription factors and for another nuclear factor; 3) potential binding sites for the chromosome "scaffold".

Base Sequence↗

Transformation of Saccharomyces cerevisiae and Schizosaccharomyces pombe with linear plasmids containing 2 micron sequences.

Linear plasmids were constructed by adding telomeres prepared from Tetrahymena pyriformis rDNA to a circular hybrid Escherichia coli-yeast vector and transforming Saccharomyces cerevisiae. The parental vector contained the entire 2 mu yeast circle and the LEU gene from S. cerevisiae. Three transformed clones were shown to contain linear plasmids which were characterized by restriction analysis and shown to be rearranged versions of the desired linear plasmids. The plasmids obtained were imperfect palindromes: part of the parental vector was present in duplicated form, part as unique sequences and part was absent. The sequences that had been lost included a large portion of the 2 mu circle. The telomeres were approximately 450 bp longer than those of T. pyriformis. DNA prepared from transformed S. cerevisiae clones was used to transform Schizosaccharomyces pombe. The transformed S. pombe clones contained linear plasmids identical in structure to their linear parents in S. cerevisiae. No structural re-arrangements or integration into S. pombe was observed. Little or no telomere growth had occurred after transfer from S. cerevisiae to S. pombe. A model is proposed to explain the genesis of the plasmids.

Ascomycota↗