Expression and polysome association of YB-1 in various tissues at different stages in the lifespan of mice

• Published in: Biochimica et biophysica acta Vol. 1760; no. 11; pp. 1675 - 1681
• Main Authors: Miwa, Arisa, Higuchi, Takashi, Kobayashi, Shunsuke
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2006
• Subjects: Animals; Brain - growth & development; Brain - metabolism; Differential stages in the lifespan; Expression; Gene Expression Regulation; Liver - growth & development; Liver - metabolism; Lung - growth & development; Lung - metabolism; Mice; Organ Specificity; Polyribosomes - metabolism; Polysome association; Tissue-specific manner; Y-box protein; Y-Box-Binding Protein 1 - metabolism; Y-box protein; Polysome association; Tissue-specific manner; Expression; Differential stages in the lifespan
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2006.08.027

Tissue-specific translational regulation is important for gene expression. YB-1 binds to mRNAs to form mRNPs and affects translation. In this study we investigated expression and polysome association of YB-1 in various tissues at different stages in the lifespan of mice. YB-1 levels decreased markedly with growth in brain, heart and muscle, but increased in the spleen. In lung, kidney and testis, the levels of YB-1 diminished with aging. In liver, no significant change in the level of YB-1 was observed throughout life. We further showed that the distribution pattern of YB-1 on a sucrose gradient differed according to tissue. Moreover, the distribution pattern of YB-1 changed drastically with growth in the liver. In 5-day-old liver, YB-1 was distributed almost exclusively in nonpolysomal fractions, whereas in 4-week-old liver, it was associated with heavy-sedimenting polysomes, as was the case in 5-day-old brain. Immunohistochemical analysis revealed that YB-1 is mainly a cytoplasmic protein in these tissues. Our results indicate that the expression and polysome association of YB-1 are regulated with growth or aging in a tissue-specific manner, presumably to control gene expression at the translational level in each tissue.