2024-03-28T12:51:59Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/246782022-04-06T07:43:38Zcom_10261_22com_10261_1com_10261_86col_10261_275col_10261_339
00925njm 22002777a 4500
dc
Vallejo, Carmen G.
author
Seguido, Ana M.
author
Testillano, P. S.
author
Risueño, María Carmen
author
2005-07
Microtubules are made from polymers of alpha/beta dimers. We have observed in rat liver that, on the first day after birth, alpha-subunit is relatively high and beta-subunit low with respect to adult values. In the hypothyroid neonate, both subunits were found to be low, therefore indicating that thyroid hormone (TH) regulates these developmental changes. TH was also found to activate tubulin expression in adult liver, especially beta-subunit. To investigate the role of TH receptors (TRs) in tubulin expression, we analyzed mice lacking TRalpha or TRbeta compared with the wild type in both normal and TH-deprived adult animals. The results suggest that, in vivo, beta-tubulin protein expression in the liver is primarily under TRbeta positive control. In euthyroid mice lacking TRbeta, beta-tubulin expression was low. However, in the corresponding hypothyroid animals, it was found increased, therefore suggesting that the unliganded TRalpha might also upregulate beta-tubulin expression. Accordingly, TH administration to hypothyroid TRbeta-deprived mice reduced their high beta-tubulin expression. In parallel, the relatively high messenger level observed with these hypothyroid animals was reduced to the euthyroid level after T(3) treatment. The microtubular network of the mutant livers appeared, by immunofluorescence confocal microscopy, generally disorganized and drastically reduced in beta-tubulin in mice lacking TRbeta. In conclusion, our results indicate that beta-tubulin is critically controlled by TRbeta in the liver and that both TRs are probably needed to maintain the microtubular network organization of the liver.
American Journal of Physiology - Endocrinology and Metabolism 289(1): E87-E94 (2005)
0193-1849
http://hdl.handle.net/10261/24678
10.1152/ajpendo.00436.2004
Rat
Knockout mice
Northern analysis
Western analysis
Histological examination
Immunofluorescence confocal microscopy
Thyroid hormone regulates tubulin expression in mammalian liver. Effects of deleting thyroid hormone receptor-α or -β