Dynamics of gene expression for microtubule-associated protein MAP1B, embryonic alpha-tubulin and late neural beta-tubulin mRNAs in the hippocampus of aged rats.
In the present study we characterized the developmental changes in the prevalence of mRNA coding for microtubule-associated protein, MAP1B, embryonic alpha-tubulin and late neural beta-tubulin in rat hippocampus and forebrain from 1 to 720 days of age using RNA gel-blot analysis. We find that (i) the microtubule-associated protein, MAP1B, signal was relatively abundant at early postnatal stages when compared with mature animals. The hybridization signal in the 24-month-old rats was was approximately 1.7 times that observed in 6-month-old rats. (ii) Embryonic alpha-tubulin and late neural beta-tubulin were differentially regulated during rat brain development. This regulation is characterized by a dramatic decrease in the amount of alpha-tubulin after day-1 and a coincident increase in the production of late neural beta-tubulin. Both messages became stabilized at moderate levels during the subsequent developmental stages. However, the averaged signal for beta-tubulin was then approximately 1.8-fold increased in 24- vs. 6-month-old rats. These results are consistent with hypothesis of an age-associated increase in reactive synaptogenesis where the healthy neurons sprout new connections to compensate for neuronal loss occurring in neighboring neurons.
Wagner
A P
AP
Institute of Gerontology, University of Erlangen-Nürnberg, Germany.
Reck
G
G
Platt
D
D
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000254:growth & development / Q000502:physiology*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D014404:Tubulin / Q000235:genetics*
D008869:Microtubule-Associated Proteins; D012333:RNA, Messenger; D014404:Tubulin; C085284:microtubule-associated protein 1B; D004247:DNA