A genetic screen using a library of 6,961 siRNAs led to the identification of SHP-1 (PTPN6), a tumor suppressor frequently mutated in malignant lymphomas, leukemias, and prostate cancer, as a potential synthetic lethal partner of the DNA repair protein polynucleotide kinase/phosphatase (PNKP). After confirming the partnership with SHP-1, we observed that codepletion of PNKP and SHP-1 induced ap...

We have studied the accuracy of DNA synthesis in vitro by purified avian myeloblastosis virus (AMV) DNA polymerase (“reverse transcriptase”) using synthetic polynucleotide templates. The enzyme catalyzes the incorporation of an exceptionally large number of incorrectly paired bases when copying ribopolynucleotide and deoxyribopolynucleotide templates. The frequency of error is approximately 1 i...

Experiments with an RNA-dependent RNA polymerase ("replicase") purified from Escherichia coli infected with an RNA bacteriophage (Qbeta) demonstrate that the enzyme generates a polynucleotide of the same molecular weight as viral RNA; the "replicase" cannot distinguish the polynucleotide from its own RNA genome. By starting reactions at input ratios below the saturation levels of template to en...

An improved method for extraction of plant DNA is described. Quantitative species comparisons based on DNA-DNA hybridization are reported for several members of the family Leguminosae and for barley, wheat and rye. A maximum of about 10% homology in DNA polynucleotide sequences is found between monocotyledons and dicotyledons tested, whereas 20 to 90% homology is observed within a family. Speci...

A simple and efficient method for in vitro mutagenesis and recombination of polynucleotide sequences is reported. The method involves priming template polynucleotide(s) with random-sequence primers and extending to generate a pool of short DNA fragments which contain a controllable level of point mutations. The fragments are reassembled during cycles of denaturation, annealing and further enzym...