Combining the CRISPR Activation and Interference Capabilities Using dCas9 and G-Quadruplex Structures.

We demonstrate that both CRISPR interference and CRISPR activation can be achieved at RNA and protein levels by targeting the vicinity of a putative G-quadruplex forming sequence (PQS) in the promoter with nuclease-dead Cas9 (dCas9). The achieved suppression and activation in Burkitťs Lymphoma cell line and in studies are at or beyond those reported with alternative approaches. When the template strand (contains the PQS) was targeted with CRISPR-dCas9, the G-quadruplex was destabilized and mRNA and protein levels increased by 2.

Reusable Microfluidic Chambers for Single-Molecule Microscopy.

Maintaining a consistent environment in single-molecule microfluidic chambers containing surface-bound molecules requires laborious cleaning and surface passivation procedures. Despite such efforts, variations in nonspecific binding and background signals commonly occur across different chambers. Being able to reuse the chambers without degrading the surface promises significant practical and fundamental advantages; however, this necessitates removing the molecules attached to the surface, such as DNA, proteins, lipids, or nanoparticles.

Stalling of Transcription by Putative G-quadruplex Sequences and CRISPR-dCas9.

Putative G-quadruplex forming sequences (PQS) have been identified in promoter sequences of prominent genes that are implicated among others in cancer and neurological disorders. We explored mechanistic aspects of CRISPR-dCas9-mediated gene expression regulation, which is transient and sequence specific unlike alternative approaches that lack such specificity or create permanent mutations, using the PQS in tyrosine hydroxylase () and promoters as model systems. We performed ensemble and single molecule investigations to study whether G-quadruplex (GQ) structures or dCas9 impede T7 RNA polymerase (RNAP) elongation process and whether orientation of these factors is significant.

Child lead exposure near abandoned lead acid battery recycling sites in a residential community in Bangladesh: Risk factors and the impact of soil remediation on blood lead levels.

Lead is a potent neurotoxin that is particularly detrimental to children's cognitive development. Batteries account for at least 80% of global lead use and unsafe battery recycling is a major contributor to childhood lead poisoning. Our objectives were to assess the intensity and nature of child lead exposure at abandoned, informal used lead acid battery (ULAB) recycling sites in Kathgora, Savar, Bangladesh, as well as to assess the feasibility and effectiveness of a soil remediation effort to reduce exposure.