BNAs dramatically improve the specificity of CRISPR-Cas9!
Cromwell et al. in 2020 reported that the incorporation of bridged nucleic acids, BNAs, at specific positions within CRISPR-RNAs (crRNAs) significantly improves Cas9 DNA cleavage specificity in vitro and cells. The researchers reasoned that modified crRNAs enhance specificity by impairing the formation of the stable “zipped” conformation during hybridization to off-target sequences. These results indicate that BNA modified crRNA improve the specificity of the CRISPR-Cas9 system and also illustrate the power of recently developed synthetic nucleic acid technologies to solve problems in enzyme specificity. |
I-motif DNA structures in the cell nuclei
DNA can fold into different structures such as G-quadruplexes and i-motifs. These DNA structures interrupt normal DNA base pairing. I-motifs are formed by a set of cytosines that pair with protonated cytosines, connecting U-shaped DNA strands. Zeraati et al. (2020) now report that i-motif structures are formed in regulatory regions of the human genome, including in promoter and telomeric regions.
To detect i-motif structures in human cells, the research group used fluorescent-dye-labeled antibody fragments that bind i-motifs with high selectivity and affinity. The study showed that i-motifs were present in gene promoter regions and telomeres. These findings suggest that i-motifs are regulatory elements in the genome.
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Vitamin B6 helps remember dreams
Vitamine B6 or pyridoxine is commonly found in food and also used as a dietary supplement. Recently researchers have observed that supplementation with vitamin B6 before bed can enhance the vividness and recall of dreams. Vitamin B6 refers to a group of water-soluble compounds essential for human health which can be analyzed using HPLC. Foods such as whole grains cereals, legumes, fruits, for example, bananas and avocados, vegetables, milk, cheese, eggs, red meat, liver, and fish, all contain vitamin B6. Aspy et al. in 2020 investigated the effect of vitamin B6 supplementation before going to bed and found that vitamin B6 significantly increased the amount of dream content recalled in a dose-dependent manner. |