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

A Miwa, T Higuchi, S Kobayashi - Biochimica et Biophysica Acta (BBA) …, 2006 - Elsevier
A Miwa, T Higuchi, S Kobayashi
Biochimica et Biophysica Acta (BBA)-General Subjects, 2006Elsevier
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 …
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.
Elsevier