Efficient DNA repair is critical for cell survival and the maintenance of genome integrity. The homologous recombination pathway is responsible for the repair of DNA double-strand breaks within cells. Initiation of this pathway in bacteria can be carried out by either the RecBCD or the RecFOR proteins. An important regulatory player within the RecFOR pathway is the RecOR complex that facilitate...

DNA origami and single-stranded tile (SST) are two proven approaches to self-assemble finite-size complex DNA nanostructures. The construction elements appeared in structures from these two methods can also be found in multi-stranded DNA tiles such as double crossover tiles. Here we report the design and observation of four types of finite-size lattices with four different double crossover tile...

Molecular beacons are sensitive fluorescent probes hybridizing selectively to designated DNA and RNA targets. They have recently become practical tools for quantitative real-time monitoring of single-stranded nucleic acids. Here, we comparatively study the performance of a variety of such probes, stemless and stem-containing DNA and PNA (peptide nucleic acid) beacons, in Tris-buffer solutions c...

Pentablock copolymers PMA-PPO-PEO-PPO-PMA synthesized via atom transfer radical polymerization (ATRP) were self-assembled with varying amounts of γ-CDs to prepare poly(pseudorotaxanes) (PPRs). When the concentration of γ-CDs was lower, the central PEO segment served as a shell of the micelles and was preferentially bent to pass through the γ-CD cavity to construct double-chain-stranded tight-fi...

We describe four monoclonal antibodies (MAB) which specifically recognize double-stranded RNA (dsRNA) together with their use in new methods for detecting and characterizing dsRNA in unfractionated nucleic acid extracts. The specificity of the antibodies was analyzed using a panel of 27 different synthetic and naturally occurring nucleic acids. All four antibodies reacted in a highly specific m...

We have examined melanocytic cells derived directly from fresh biopsy tissue for the presence of p53 mutations. Using selective media that permits growth of melanocytes and inhibits growth of fibroblasts and keratinocytes, we established short-term, primary cultures of melanocytes from skin biopsies of common acquired nevi, dysplastic nevi, and from metastatic melanoma. Using PCR-single-strande...

We present evidence for the existence of an additional long-range interaction in vertebrate U1 snRNAs. By submitting human U1 snRNP, HeLa nuclear extracts, authentic human or X. laevis in vitro transcribed U1 snRNAs to RNase V1, a nuclease specific for double-stranded regions, cleavages occurred in the sequence psi psi ACC (positions 5-9) residing in the 5' terminal region of the RNA. The RNase...

Recently, Rogers and Crocker (1) proposed a method to predict the interaction between colloids coated with two kinds of ssDNA, A and B. A key step in ref. 1 was to estimate the average number of DNA bonds, 〈N〉, assuming local chemical equilibrium (LCE) between hybridized and unhybridized sticky end concentrations: hNi 1⁄4 Ð dr CAðrÞCBðrÞ exp1⁄2− βΔG0 ρ0 1⁄4 Ð dr1⁄2CAðrÞ−CABðrÞ 1⁄2CBðrÞ−CABðrÞ e...

We investigate the translocation of a single-stranded DNA through a pore which fluctuates between two conformations, using coupled master equations. The probability density function of the first passage times of the translocation process is calculated, displaying a triple-, double-, or monopeaked behavior, depending on the interconversion rates between the conformations, the applied electric fi...