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The 31mer 5'-TCA ACG CTA GAA TTC GGA TCC ATC GCT TGG T, the complementary 33mer 5'-CCA AGC GAT GGA TCC GAA TTC TAG CGT TGA GAT, the 40mer 5'-GGC CAG GAT GGT GAA GAA TTC GAT CCG GTA CGT AGC TAA G, and the complementary 42mer 5'-TAC TTA GCT ACG TAC CGG ATC GAA TTC TTC ACC ATC CTG GCC were synthesized and their reactivity towards EcoRI was studied. It was found that the 31mer and the 40mer were cleaved at a comparable rate to the 31mer-33mer hybrid and the 40mer-42mer hybrid, respectively. The rate of cleavage of the 33mer and the 42mer was an order of magnitude lower. To rule out possible intermolecular duplex formation, the 33mer was immobilized on cellulose by ligation and labeled with alpha 32P-dCTP using Klenow fragment of E. coli DNA polymerase. EcoRI cleaved this immobilized oligomer into specific fragments.

This paper reports details of the synthesis of oligodeoxynucleotides containing the modified base 5-methyl-N4,N4-ethanocytosine (Ce). The 9-fluorenylmethoxycarbonyl group is used as a protecting group for the exocyclic amines of dA and dC. This group can be removed rapidly under very mild conditions. Oligomers containing the Ce base form a cross-link when hybridized to their complementary deoxyoligonucleotides. Some of the scope and limitations of these cross-link forming oligonucleotides are reported.

In order to gain more understanding about the mode of action of DNA polymerase, eight related partially self-complementary "hairpin" shaped oligodeoxynucleotides were prepared. Four of the oligomers contained either 1-beta-D-arabinofuranosyluracil (ara-U) or 1-beta-D-2'deoxyxylofuranosylthymine (dxT) nucleoside analogs at their 3' termini. We investigated the ability of the oligomers to prime DNA synthesis in relationship to the stability of the hybridized region, the nature of the sugar terminus and the DNA polymerase used (reverse transcriptase, or polymerase alpha). The results are discussed in relation to the mode of action of some nucleoside analog inhibitors of DNA polymerase. An understanding of the mechanism of DNA polymerase action was used to design template-primer analogs as polymerase inhibitors. Two of the oligodeoxynucleotide analogs prepared were found to be potent inhibitors of polymerase alpha.