Partial sequence homologies between cytoskeletal proteins, <i>c-myc</i>, Rous sarcoma virus and adenovirus proteins, transducin, and β- and γ-crystallins

Abstract

Computer based sequence comparisons indicate partial sequence homology between human c-myc, Rous sarcoma virus, adenovirus 7, and simian sarcoma virus proteins and the cytoskeletal proteins d9smin, keratin and vimentin. In addition, sections of the oncogene proteins showed partial but significant homology to alpha and gamma subunits of transducin. gamma-II and beta-BP crystallins showed partial but significant homology to the cytoskeletal proteins keratin, vimentin, desmin, alpha and beta-tubulin, and to adenovirus 7 and simian sarcoma virus transforming gene proteins. Beta-BP crystallin showed partial but significant homology to Rous sarcoma virus protein, and to alpha and gamma subunits of transducin. Both crystallins showed partial sequence homology to the GTP-binding protein elongation factor TU from Escherichia coli. These sequence homologies suggest a link between the mechanisms of normal lens cell differentiation, involving modifications to the cytoskeleton and subsequent changes to the pattern of protein synthesis, and mechanisms of neoplastic transformation. Furthermore, the transducin-like region on beta-crystallin may be important for its interaction with lens membranes and the maintenance of short-range order for lens transparency.