ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
—Heterogeneity among the primary translation products of rat brain tubulin messenger RNA was examined. On two-dimensional gels native cytoplasmic tubulin from randomly bred rats (PB21) consists of two groups of α tubulin subunits among which the most acidic forms, α1 and α2, are most abundant; and β tubulin consists of a minimum of two species, β1 and β2. In the same group of animals the primary translation products of rat brain tubulin mRNA consist of at least these four subunit forms (α1α2, β1 and β2); however, minor basic forms of α subunits were not synthesized. This same result was obtained from a homologous brain protein synthesizing system, a heterologous system prepared from brain polysomes and rabbit reticulocyte initiation factors, and a wheat germ lysate programmed with brain poly A mRNA. A variant form of brain tubulin was found in rats bred monogamously for over 30 generations (MB71 rats). MB71 brain polysomes synthesize overlapping a subunits which migrate in two-dimensional gels to the α1 position, and the typical PB21 α2 is not present. The addition of PB21 brain mRNA to a protein synthesizing system composed of MB71 polysomes plus reticulocyte initiation factors allowed synthesis of the typical α2 tubulin in addition to the MB71 tubulin subunits. The structural relationship among subunits was examined by radioiodinated peptide mapping. The α subunits are structurally different from the β subunits; however, among the major tyrosine-containing tryptic peptides no prominent differences were observed between α1 and α2, or between β1 and β2 by the radioiodination procedure. The results provide evidence for heterogeneity among the primary translation products of brain tubulin mRNA, and for the existence of multiple functional tubulin genes in rat brain.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1979.tb11725.x
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