DNA cleavage by the Type III Restriction-Modification enzymes requires communication in 1D between two distant indirectly-repeated recognitions sites, yet results in non-specific dsDNA cleavage close to only one of the two sites. To test a recently proposed ATP-triggered DNA sliding model, we addressed why one site is selected over another during cleavage. We examined the relative cleavage of a...

We have reported previously that Short Interspersed Degenerate Retroposons of the SIDER2 subfamily, largely located within 3'UTRs of Leishmania transcripts, promote rapid turnover of mRNAs through endonucleolytic cleavage within the highly conserved second tandem 79-nt hallmark sequence (79-nt SII). Here, we used site-directed mutagenesis and in silico RNA structural studies to delineate the ci...

Cell entry by paramyxoviruses requires fusion of the viral envelope with the target cell membrane. Fusion is mediated by the viral fusion (F) glycoprotein and usually requires the aid of the attachment glycoprotein (G, H or HN, depending on the virus). Human respiratory syncytial virus F protein (F(RSV)) is able to mediate membrane fusion in the absence of the attachment G protein and is unique...

The deep-sequencing of small RNAs has revealed that different numbers and proportions of miRNA variants called isomiRs are formed from single miRNA genes and that this effect is attributable mainly to imprecise cleavage by Drosha and Dicer. Factors that influence the degree of cleavage precision of Drosha and Dicer are under investigation, and their identification may improve our understanding ...

Various antitumor drugs stabilize DNA topoisomerase II-DNA transient covalent complexes. The complexes distribution along pBR322 DNA was shown previously to depend upon the nature of the drug (Tewey et al. (1984) Science 226, 466-468). The position in pBR322 of DNA cleavage by calf DNA topoisomerase II for 115 such sites stabilized by an ellipticine derivative and the relative frequency of clea...

In Arabidopsis, microRNA-directed cleavage can define one end of RNAs that then generate phased siRNAs. However, most miRNA-targeted RNAs do not spawn siRNAs, suggesting the existence of additional determinants within those that do. We find that in moss, phased siRNAs arise from regions flanked by dual miR390 cleavage sites. AtTAS3, an siRNA locus important for development and conserved among h...

Methods. Soluble and insoluble lens proteins from 4-day-old to 4-month-old rat lens cortexes and nuclei were separated by two-dimensional electrophoresis. The insoluble proteins from 4-month-old nuclei were electroblotted and the NH2 termini of proteins sequenced. Cleavage sites appearing at 4 months of age were compared to cleavage sites produced by purified calpain II and to cleavage sites ap...

Eukaryotic DNA topoisomerase I introduces transient single-stranded breaks on double-stranded DNA and spontaneously breaks down single-stranded DNA. The cleavage sites on both single and double-stranded SV40 DNA have been determined by DNA sequencing. Consistent with other reports, the eukaryotic enzymes, in contrast to prokaryotic type I topoisomerases, links to the 3'-end of the cleaved DNA a...

A critical step during human microRNA maturation is the processing of the primary microRNA transcript by the nuclear RNaseIII enzyme Drosha to generate the approximately 60-nucleotide precursor microRNA hairpin. How Drosha recognizes primary RNA substrates and selects its cleavage sites has remained a mystery, especially given that the known targets for Drosha processing show no discernable seq...

Edman phosphate ((32)P) release sequencing provides a high sensitivity means of identifying phosphorylation sites in proteins that complements mass spectrometry techniques. We have developed a bioinformatic assessment tool, the cleavage of radiolabeled protein (CRP) program, which enables experimental identification of phosphorylation sites via (32)P labeling and Edman degradation of cleaved pr...