We previously reported the first molecular mechanism underlying the age-related homeostasis, ASE/AIE-mediated genetic mechanism for age-related regulation of gene expression, which turned out to be a mechanism of puberty-onset gene switching, specifically controlling a group of genes for their expression from puberty into old age (Kurachi & Kurachi J Thromb Haemost 2005;

Zahng et al J Biol Chem 277:4532, 2002
;
Kurachi et al Science 285:739, 1999
). This led us to successful construction of a transgenic mouse model of hemophilia B Leyden, a unique subset of hemophilia B with its mechanism being remained mysterious, robustly mimicking its unusual pattern of puberty-onset spontaneous amelioration. With this background, we hypothesized that besides the ASE/AIE-mediated mechanism, there exist more unidentified fundamental regulatory mechanisms for age-related homeostasis, which individually or in various combinations generate age-related complex and dynamic regulatory patterns of liver proteins. We launched a series of global and quantitative analysis of age-related changes in expression of liver nuclear proteins of mice (C57BL/6xSJL, [male], 1 through-24 month of age) by taking a procedure composed of two-dimensional gel electrophoresis (2DE) for separation and quantification of liver nuclear protein spots and of MALDI-TOF/MS PMF analyses to identify proteins in the spots. Out of over 6000 spots recognized and quantified in 2DE, 4547 protein spots were subjected to MALDI-TOF/MS analysis for protein identification. Finally, 2765 protein spots including many isomers were found unique. Systematic analyses of their age-related expression identified several major phases in protein expression throughout the lifespan. These findings supported our hypothesis that there exist multiple novel molecular mechanisms responsible for maintaining age-related homeostasis. The comprehensive liver nuclear protein data set was then used to construct a comprehensive database, which allows rapid and reliable searches for expression of specific proteins, their age-related dynamic profiles, isomers, protein identification from 2DE image, and other related information. This will serve as a valuable platform resource for studying epigenetic challenges, evaluation of drugs as well as gaining further insights into the molecular mechanisms underlying age-related homeostasis.

Disclosure: No relevant conflicts of interest to declare.

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