The nonhistone chromosomal proteins of vertebrate liver and kidney: a comparative study by gel electrophoresis.

The nonhistone chromosomal proteins (NHC proteins) probably include enzymes of chromosomal metabolism, general structural proteins, and possibly control elements. In theory, these proteins may have been strongly conserved during evolution, as the histones have. We have used sodium dodecyl sulfate (SDS) disc gel electrophoresis to analyze and compare the NHC proteins of two tissues, liver and kidney, from rat, cat, cow, chicken, turtle, and frog. The gel patterns indicate that the NHC proteins have changed much more during evolution than have the histones; the total pattern of NHC proteins has not been conserved. However, there does appear to be a conservation of a subset of bands for each tissue investigated. Further chemical analysis will be required to establish the significance of the results.