Ncl can refer to nucleolin, a multifunctional protein. It mainly localizes in the nucleolus, but is also found in the nucleoplasm, cytoplasm, and cell membrane. Its three main structural domains enable it to interact with different proteins and RNA sequences. Ncl is involved in multiple biological processes such as ribosome biogenesis, chromatin organization, DNA and RNA metabolism, cell proliferation, angiogenesis, apoptosis regulation, stress response, and microRNA processing [1].

Ncl has been increasingly associated with pathological processes, especially tumorigenesis and viral infection. For example, it has been shown that Ncl can inhibit the growth of peste des petits ruminants virus (PPRV). When the expression level of Ncl was inhibited with small interfering RNAs, PPRV growth was improved, while an increase in Ncl expression inhibited PPRV proliferation. This inhibitory effect was due to Ncl stimulating the interferon (IFN) pathways in host cells [2].

In conclusion, Ncl is a multifunctional protein with diverse roles in normal biological processes and pathological conditions. Its functions in tumorigenesis and viral infection, as revealed through studies like those on PPRV, highlight its significance in understanding disease mechanisms, providing potential targets for anti-tumor and anti-viral strategies.