Hairpin opening by single-strand-specific nucleases.

AUTOR(ES)

Kabotyanski, E B

RESUMO

DNA molecules with covalently sealed (hairpin) ends are probable intermediates in V(D)J recombination. According to current models hairpin ends are opened to produce short single-stranded extensions that are thought to be precursors of a particular type of extra nucleotides, termed P nucleotides, which are frequently present at recombination junctions. Nothing is known about the activities responsible for hairpin opening. We have used two single-strand-specific nucleases to explore the effects of loop sequence on the hairpin opening reaction. Here we show that a variety of hairpin ends are opened by P1 nuclease and mung bean nuclease (MBN) to leave short, 1-2 nt single-stranded extensions. Analysis of 22 different hairpin sequences demonstrates that the terminal 4 nt of the hairpin loop strongly influence the sites of cleavage. Correlation of the nuclease digestion patterns with structural (NMR) data for some of the hairpin loops studied here provides new insights into the structural features recognized by these enzymes.

Documentos Relacionados

• Linker histones affect patterns of digestion of supercoiled plasmids by single-strand-specific nucleases.
• Mechanism of replication of bacteriophage phi X174 XX. Sensitivity of nascent DNA to single-strand-specific nucleases.
• DNA hairpin loops in solution. Correlation between primary structure, thermostability and reactivity with single-strand-specific nuclease from mung bean.
• Assay of deoxyribonucleic acid homology using a single-strand-specific nuclease at 75 C.
• Stable DNA unwinding, not "breathing," accounts for single-strand-specific nuclease hypersensitivity of specific A+T-rich sequences.