David Baltimore and the advent of eukaryotic RNA-binding proteins.

The late David Baltimore will long be remembered as a towering figure in the modern era of virology and immunology. But less well known is that early in his career, he discovered the existence of eukaryotic RNA-binding proteins, in collaboration with Alice Huang. This work was an extension of previous experiments he had done in which poliovirus RNA added to HeLa cell cytoplasmic extracts underwent an increase in its sucrose gradient sedimentation velocity. The subsequent work revealed the existence of a soluble pool of RNA-binding proteins and had two impacts. On the one hand, it was the beginning of the eukaryotic RNA-binding protein field. On the other hand, it led some investigators to challenge the reality of isolated mRNP complexes. As we know, the latter concern was settled by the introduction of in vivo UV-mediated RNA-protein crosslinking. The mRNA-protein interaction landscape now is at a very advanced and richly enabling stage, but as always in scientific epistemology, it is appropriate to recall from whence it arose.