Development of a novel DsRed-NLS vector with a monopartite classical nuclear localization signal

The nuclear localization signal (NLS) marks proteins for transport to the nucleus and is used in various applications in many fields. NLSs are used to achieve efficient and stable transport of biomolecules. Previously, commercial vectors used in NLS studies contained three iterations of the NLS sequence, but these sequences can affect experimental results and alter protein function. Here, we investigated a new vector using a single classical NLS sequence with a mutation in pDsRed2-C1-wt to reduce experimental artifacts. In the newly constructed pDsRed2-C1-1NLS vector, the NLS sequence is placed near the multiple cloning sites of pDsRed2-C1-wt, and the multiple cloning site region was designed to facilitate insertion of the desired gene by site-directed mutagenesis. Fluorescent protein expression in the nucleus can be visually confirmed. The results show that the fluorescent protein was bound to the transport protein. The constructed vector had a cell survival rate of 89-95% and a transfection efficiency of 39-56% when introduced into animal cells, which are similar to those of other NLS vectors. Additionally, the constructed NLS vector can be used to demonstrate complementary binding between target proteins, and that the target protein is transported by the NLS transport system. Especially, we show that the vector can be useful for experiments involving the S100A10 gene. In addition, the constructed vector is useful for studies of genes and proteins that show potential for gene therapy or drug delivery applications.

Influence of swabbing solution and swab type on DNA recovery from rigid environmental surfaces

Determination of the metagenome has become an important component of forensic identification, which requires efficient environmental sampling techniques. Therefore, in this study, we compared the efficiency of sample collection using swabbing with cotton swabs and three types of medical swabs (S7, S22, S24) along with three different solutions: phosphate-buffered saline (PBS), 1% Tween 20 + 1% glycerol in PBS (TG), and GS commercial solution (Noble Bio, Hwaseong, Republic of Korea). Combinations of the three solutions with the three types of swabs were tested at different volumes (cotton swab, S7: 0, 30, 50, 70 μL; S22, S24: 0, 70, 100, 130 μL). Escherichia coli and Staphylococcus aureus were selected as representative environmental microbial samples, and the number of colony-forming units (CFUs), DNA concentration, and DNA copy numbers were compared across groups. The sampling process had a clear effect on the efficiency of extraction, which allowed for determination of a more efficient sample sampling method. In particular, cotton swabs showed 2-10-fold greater CFUs of both species than the medical swabs, and resulted in significantly greater amounts of extracted DNA. TG was found to be the most efficient solution for bacterial DNA extraction, with higher CFUs and DNA obtained than with the other three solutions at all volumes tested. This study highlights the need for a standardized sampling method that can be applied to all environmental samples, especially for microbial quantification, and provides valuable reference data for the efficient collection of environmental samples for metagenomic analyses in microbial-based forensic assessments.