nos promoter sequences drive expression of mCherry that is tagged at the N-terminal end with a Tag:NLS(Unk) nuclear localization signal and at the C-terminal end with Tag:MCP. An αTubulin 3' UTR is present. In the presence of a mRNA tagged with Tag:MS2 (an RNA stem loop to which Tag:MCP binds), the mCherry-Tag:MCP fusion protein can bind to this tagged mRNA, allowing its localization within the cell to be studied. In the absence of a Tag:MS2-tagged mRNA (or when unbound), the mCherry-Tag:MCP fusion protein is targeted to the nucleus due to the presence of the Tag:NLS(Unk) tag.