Developmental regulation of microtubule-associated protein 2 expression in regions of mouse brain.
The relative levels of microtubule-associated protein 2(MAP2) were determined during postnatal development of the mouse in six different discrete brain regions: cerebellum, cortex, hippocampus, olfactory bulb, brainstem, and hypothalamus. Brain homogenates were electrophoresed on sodium dodecyl sulfate-containing gels and analyzed by immunoblotting with MAP2-specific antibodies. The levels of MAP2 in each region were determined using radiolabeled secondary antibodies and densitometric quantification of the autoradiograms over a range that was determined to have a linear response. The results indicated that in all regions and at all ages there was only one high-molecular-weight polypeptide of MAP2, which did not change in electrophoretic mobility after dephosphorylation. In most regions, the levels of MAP2 increased during the first 2 postnatal weeks. However, there were differences in the time course and relative levels of MAP2 between regions. In addition, all regions of the brain expressed the low-molecular-weight form of MAP2 (MAP2c) that was present at birth as a heterogeneous group of polypeptides with an apparent molecular weight of 70K. Most of the heterogeneity of MAP2c, however, was eliminated after dephosphorylation. The levels of MAP2c decreased dramatically after 2 weeks postnatally, except for the olfactory bulb, where the levels of MAP2c remained relatively high even in adults.
Crandall
J E
JE
Department of Developmental Neurobiology, E. K. Shriver Center for Mental Retardation, Waltham, MA 02254.
Fischer
I
I
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009830:Olfactory Bulb / Q000378:metabolism; D009928:Organ Specificity; D010766:Phosphorylation
D008869:Microtubule-Associated Proteins