ABSTRACT
This chapter focuses on the authors' studies of changes induced in nonhistone chromatin (NHC) proteins during chemically induced and spontaneous murine hepatocarcinogenesis. Particular attention is directed at pointing out potential problems during isolation of chromatin and chromosomal proteins. Chromatin extraction in high salt-urea buffers proved most reliable in terms of yield of extracted chromosomal proteins, recovery, and satisfactory electrophoretic resolution. The chapter describes the use of high-resolution multiple linear gradient two-dimensional electrophoresis, silver staining of resolved polypeptides, and computer-assisted image processing in the study of NHC proteins in normal and neoplastic tissue. Chromatin represents the interphase state of chromosomes in eukaryotic cell nuclei consisting of a macromolecular complex composed of DNA, RNA, and protein. The chapter explores two basic hepatocarcinogenic regimen in Sprague-Dawley and ACI male rats to produce discrete carcinogenic stages and primary hepatocellular carcinomas for analysis. Mice harboring spontaneous carcinomas are detected by use of a radioimmunoassay for α-fetoprotein serum level.
