PLANT PHYSIOLOGY , Vol 105, Issue 4 1347-1353, Copyright © 1994 by American Society of Plant Biologists
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DEVELOPMENT AND GROWTH REGULATION |
Changes in the Accumulation of [alpha]- and [beta]-Tubulin Isotypes during Cotton Fiber Development
D. C. Dixon, R. W. Seagull and B. A. Triplett
United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, P.O. Box 19687, New Orleans, Louisiana 70179
The expression of [alpha]- and [beta]-tubulin proteins in developing fibers
and several other tissues of cotton (Gossypium hirsutum, cv Texas Marker 1)
have been analyzed by immunoblots of one- and two-dimensional gels
utilizing anti-tubulin antibodies as probes. As a percentage of total
protein, fibers had greater amounts of tubulin than did hypocotyls, roots,
leaves, or cotyledons. Both [alpha]- and [beta]-tubulin, having apparent
molecular masses of approximately 50 kD and isoelectric points between pH 5
and pH 6, were resolved on a single two-dimensional gel. Under the
conditions used, [alpha]-tubulin was less acidic in the isoelectric
focusing dimension and migrated slightly faster in the sodium dodecyl
sulfate dimension than did [beta]-tubulin. Nine [alpha]-tubulin isotypes
that formed two distinct groups were identified on immunoblots of
two-dimensional gels. The three most abundant [alpha]-tubulin isotypes were
common to all tissues examined. Seven distinct [beta]-tubulin isotypes were
also identified. Although their level of accumulation differed, four of the
[beta]-tubulin isotypes were common to all tissues. Preferential
accumulation of isotypes was more apparent in fibers than in the other
tissues examined. Two [alpha]-tubulin isotypes and two [beta]-tubulin
isotypes showed preferential accumulation in 10- and 20-d postanthesis
fibers, respectively.
