Lysine methylation goes global.

The process of post-translational covalent modifications of proteins represents a transcription-independent regulatory mechanism allowing rapid alteration of protein activity and function in response to various intra- and extracellular stimuli. Lysine methylation (KM) was deemed to be a constant covalent mark, providing long-term signaling, including the histone-dependent mechanism for transcriptional memory. Only recently has it become apparent that lysine methylation, similar to other covalent modifications, is transient and can be dynamically regulated by an opposing activity, de-methylation.

The p53 gene family: control of cell proliferation and developmental programs.

For a quarter of a century the gene p53 has attracted close attention of scientists who deal with problems of carcinogenesis and maintenance of genetic stability. Multicellular organisms on our planet owe their rich evolution in many respects to the ability of this gene to protect cells from oncogenic transformation and harmful changes in DNA. A relatively recent discovery of structural p53 homologs, the genes p63 and p73, which seem to have more ancient roots, has roused keen interest in their function.

[Dominant-negative inactivation of p53: the effect of the proportion between trans-dominant inhibitor and its target].

Dominant-negative mutations of the p53 tumor suppressor gene and oligomerization of the mutant and wild-type p53 are considered responsible for functional inactivation of the p53 tetramer. Although dominant-negative inactivation of p53 is well reproducible in experimental systems, its contribution to processes occurring in tumor cells heterozygous at p53 is still unclear. To study the effect of dominant-negative inhibitor GSE22 on the p53 activity, cultures coexpressing GSE22 and tetracycline-suppressible p53 were derived from p53-negative cell lines.

[Construction of chimeric tumor suppressor p53 resistant to the dominant-negative interaction with p53 mutants].

A chimeric p53 cDNA was constructed so that the fragment coding for 39 residues of the chicken p53 tetramerization domain replaced the corresponding region of human p53. The chimeric cDNA substantially inhibited the colony-forming ability of transfected human and mouse cells, suggesting a suppressory potential for its product. The chimeric p53 activated promoters containing p53-responsive elements.