Cytokeratin of apparent high molecular weight in livers from griseofulvin-fed mice.

Livers from mice fed griseofulvin (GF) for 12 months contain abnormal cytokeratin (CK) intermediate filaments (IFs) that aggregate to form Mallory bodies (MBs). Sections from control and GF-treated livers were extracted with Triton X-100. IF-enriched fractions were analyzed by gel electrophoresis and IF proteins were identified by Western blotting using anti-CK 55 (TROMA 1) and CK 49 (TROMA 2), and the anti-'universal' IF known as aIF. Western blotting on control and GF-treated livers with TROMA 1 and TROMA 2 obtained with gels loaded with 2 micrograms of protein revealed the presence of CK 55 and CK 49. In contrast, when a larger amount of protein was loaded on the gel (10 or 12 micrograms) the results were different. In the control we detected bands corresponding to CK 55 and CK 49 plus a faint band at approx. 97 kDa. In the GF-treated animals, we detected a more pronounced reaction with the 97 kDa band and in addition we now detected several higher molecular weight bands which reacted with anti-CK antibodies. These results demonstrated that the induced changes in CKs in the GF liver are associated with the increase of apparent high molecular weight CK. These apparent high molecular weight CKs could be obtained by a pathological cross-linking of the preexisting liver CK monomers in different combinations such as CK 55-55, CK 49-49 and/or with other proteins.