14-3-3 proteins mediate the localization of Centrin2 to centrosome

14-3-3e and 14-3-3c localize to the centrosome and regulate centrosome duplication, by inhibiting cdc25C function. As14-3-3c and 14-3-3e form a complex with centrosomal proteins, we asked if this ability was required to regulate centrosomeduplication. The results in this report demonstrate that 14-3-3e and 14-3-3c form a complex with Centrin2 and that thebinding site is located in the N-terminal EF hand in Centrin2, EF1. A Centrin2 mutant that does not form a complex with14-3-3 proteins displays a punctate cytoplasmic localization and does not localize to the centrosome. These results suggestthat in addition to negatively regulating centrosome duplication as previously reported, 14-3-3 proteins might also berequired for centriole biogenesis by regulating the localization of Centrin2 at the centrosome.

Generation of HIV-1 based bi-cistronic lentiviral vectors for stable gene expression and live cell imaging.

The study of protein-protein interactions, protein localization, protein organization into higher order structures and organelle dynamics in live cells, has greatly enhanced the understanding of various cellular processes. Live cell imaging experiments employ plasmid or viral vectors to express the protein/proteins of interest fused to a fluorescent protein. Unlike plasmid vectors, lentiviral vectors can be introduced into both dividing and non dividing cells, can be pseudotyped to infect a broad or narrow range of cells, and can be used to generate transgenic animals. However, the currently available lentiviral vectors are limited by the choice of fluorescent protein tag, choice of restriction enzyme sites in the Multiple Cloning Sites (MCS) and promoter choice for gene expression. In this report, HIV-1 based bi-cistronic lentiviral vectors have been generated that drive the expression of multiple fluorescent tags (EGFP, mCherry, ECFP, EYFP and dsRed), using two different promoters. The presence of a unique MCS with multiple restriction sites allows the generation of fusion proteins with the fluorescent tag of choice, allowing analysis of multiple fusion proteins in live cell imaging experiments. These novel lentiviral vectors are improved delivery vehicles for gene transfer applications and are important tools for live cell imaging in vivo.