pJoseph2: a family of plasmids as positive controls for bacterial protein expression, transfections, and western blots.

Epitope tagging represents a powerful strategy for expedited identification, isolation, and characterization of proteins in molecular biological studies, including protein-protein interactions. We aimed to improve the reproducibility of epitope-tagged protein expression and detection by developing a range of plasmids as positive controls. The pJoseph2 family of expression plasmids functions in diverse cellular environments and cell types to enable the evaluation of transfection efficiency and antibody staining for epitope detection.

Phosphorylation of the Myogenic Factor Myocyte Enhancer Factor-2 Impacts Myogenesis In Vivo.

Activity of the myogenic regulatory protein myocyte enhancer factor-2 (MEF2) is modulated by post-translational modification. We investigated the in vivo phosphorylation of MEF2, and identified serine 98 (S98) as a phosphorylated residue. Phospho-mimetic (S98E) and phospho-null (S98A) isoforms of MEF2 did not differ from wild-type in their activity in vitro, so we used CRISPR/Cas9 to generate an S98A allele of the endogenous gene.