E LNA has been evaluated in several clinical trials.3-6 The most attractive aspect of LNA is that it exhibits unprecedented thermal stability towards complementary DNA and RNA. The additional ring conformationally restricts the sugar into an orientation that is particularly favorable for hybridization. A single insertion of an LNA nucleotide can enhance the melting temperature by more than 9 against RNA. This enhancement is sequence dependent and does decrease with increasing LNA content.7 It should be pointed out that this stabilization does not come at the expense of specificity. In fact, LNA’s exhibit mismatch specificity that is more often than not superior to that of DNA. In addition to its ability to bind very tightly to DNA and RNA, LNA also has several other desirable traits. Like DNA and RNA, LNA is highly soluble in water and can be therapeutically delivered using standard DNA/RNA strategies. Also, the nucleoside phosphoramidites of LNA are commercially available and can be readily used with wellestablished solid phase synthesis methods to synthesize all-LNA or LNA/ DNA/RNA chimeras.458-37-7 web Not only does this make LNA widely available, but it also allows LNA nucleotides to be interspersed among DNA and RNA nucleotides, giving researchers a high degree of design control for their desired applications. Furthermore, LNA is well-tolerated in biological systems. A lot of this is because LNA oligonucleotides do not need to be as long to exhibit tight binding to their targets. Finally, as a backbone modification, LNA is highly nuclease resistant. Fully modified LNA is very stable in the presence of intra- and extracellular endo- and exonucleases while LNA/RNA and LNA/DNA chimeras show stabilities that are sequence dependent. For example, mixmers with alternating LNA and DNA residues will be much more stable than gapmers containing a stretch DNA flanked by LNA on the 5′ and 3′ termini. situ hybridization (FISH) experiments. Another area where the use of LNA has been investigated thoroughly is in the field of antisense to modulate gene expression by inactivating mRNA. This has been predominantly done in one of two ways. In the first, all-LNA or LNA/ DNA mixmers are used as steric blocks to inhibit therapeutically interesting RNA targets, particularly those that have complex structures that make them inaccessible to typical antisense agents. In the second, DNA gapmers are used to facilitate RNase H cleavage of the RNA target.937272-79-2 MedChemExpress These sequences are usually composed of an internal DNA sequence of at least 7 nt that is sandwiched between two sections of LNA of 2-5 nt.PMID:30846224 The LNA termini provide affinity while the DNA region triggers cellular RNase H activity. As an example, Koch and coworkers have shown that a 13 nt gapmer containing an 8 nt DNA sequence was able to significantly lower non-high-density lipoprotein in both mice and nonhuman primates.9 Other areas where LNA has been used include the cleavage of RNA by DNAzymes, the detection of microRNA as well as the capture of RNA. LNA continues to be a highly desirable oligonucleotide modification. In the past, Glen Research was able to provide LNA phosphoramidites for the research and development community, but, unfortunately, they had to be discontinued. Recent developments have allowed us to again provide the tools for this technology in the form of our LA phosphoramidites, as described below. As was the case in the past, the pyrimidine bases are thymine and 5-methylcytosine rather than uracil an.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com