Higher plant tubulin identified by self-assembly into microtubules in vitro

Morejohn, Louis C.; Fosket, Donald E.

doi:10.1038/297426a0

Cited by 93 publications

(65 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Higher plant tubulin has been isolated and partially characterized (22). Antibodies raised against SDS-PAGE purified plant tubulin monomers, as well as ligand binding studies, have shown that plant tubulins have some unique biochemical properties, but share many of the characteristics of the better characterized vertebrate tubulins (10).…”

Section: Discussionmentioning

confidence: 99%

Light Regulation of β-Tubulin Gene Expression during Internode Development in Soybean (Glycine max [L.] Merr.)

Bustos

Guiltinan²,

Cyr³

et al. 1989

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

The relationship between tubulin gene expression and cell elongation was explored in developing internodes of Glycine max (L.) Merr., using light as a variable to alter the rate of elongation. Illumination of 10-day-old etiolated seedlings not only stopped first internode elongation, but also brought about a 80% decrease in the steady state level of ,-tubulin mRNA over the course of the subsequent 12 hours. This strong down regulation of j6-tubulin mRNA occurred without significant changes in the size of the soluble tubulin pool and it was accompanied by a marked increase in chlorophyll a/b binding protein mRNA.cases, the tubulin dimer pool is maintained through both transcriptional and post-transcriptional control of tubulin gene expression (1,17). Little is known about the regulation of tubulin synthesis in plants, but Cyr et al. (8) observed changes of several fold in the levels of tubulin protein and mRNA during carrot somatic embryogenesis. Furthermore, Fukuda (11) reported that the rate of tubulin synthesis increased during the formation of cortical microtubules in differentiating tracheary elements. The involvement of cortical microtubules in cell elongation and the increase in tubulin levels and in microtubule assembly which has been shown to accompany cell elongation (9, 29), make elongating tissues attractive as systems for investigating the regulation oftubulin synthesis in higher plants. Here, we show that changes in ,Btubulin mRNA steady state levels and internode elongation rates vary concomitantly in light-grown and etiolated soybean seedlings. Internodes of etiolated seedlings exhibited elongation rates that were four to five fold greater than those observed in control seedlings grown under a 12 h light/dark cycle. The rapidly elongating internodes of dark-grown seedlings exhibited proportionally higher steady-state levels of jtubulin mRNA. Furthermore, subsequent illumination of the dark-grown seedlings brought about a reduction in the rate of elongation and a concomitant decrease in the steady-state level of #-tubulin mRNA.Microtubules are formed by the regulated self-assembly of the heterodimeric protein tubulin from a soluble tubulin dimer pool, and cytoplasmic microtubules are in a dynamic equilibrium with this tubulin dimer pool (18). Since microtubules can form and persist only when the tubulin dimer concentration exceeds a critical value, maintenance of the tubulin dimer pool at a level above this critical concentration is essential for microtubule formation. Where it has been examined, tubulin synthesis is regulated by a mechanism that is sensitive to changes in the amount of assembled microtubules. In cultured mammalian cells, tubulin synthesis is autoregulated by a post-transcriptional mechanism that is responsive to the size of the tubulin dimer pool (5).

show abstract

Section: Discussionmentioning

confidence: 99%

Light Regulation of β-Tubulin Gene Expression during Internode Development in Soybean (Glycine max [L.] Merr.)

Bustos

Guiltinan²,

Cyr³

et al. 1989

Plant Physiol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Indeed, the functional consequences of these substitutions cannot be predicted a priori, so information must also be derived from direct examination of plant microtubule protein function. Although few studies exist on the regulation of plant microbutule polymerization, methods to isolate, purify, and polymerize plant tubulin (Morejohn and Fosket, 1982;Bokros et al, 1993) have facilitated studies showing that plant and mammalian tubulins are structurally, immunologically, and pharmacologically distinct (Morejohn et al, 1984;Morejohn and Fosket, 1986;Fosket and Morejohn, 1992;Hugdahl and Morejohn, 1993). We have recently shown that taxol-induced polymerization of plant tubulin proceeds more effectively, even at low temperature, and has a lower critical concentration than mammalian tubulin (Bokros et al, 1993).…”

Section: Polymerization Depends Upon a Critical Concentration (C) Ofmentioning

confidence: 99%

Unique functional characteristics of the polymerization and MAP binding regulatory domains of plant tubulin.

et al. 1993

View full text Add to dashboard Cite

An understanding of the regulation of microtubule polymerization and dynamics in plant cells requires biochemical information on the structures, functions, and molecular interactions of plant tubulin and microtubule-associated proteins (MAPs) that regulate microtubule function. We have probed the regulatory domain and polymerization domain of purified maize tubulin using MAP2, an extensively characterized mammalian neumnal MAP. MAP2 bound to the surface of preformed, taxol-stabilized maize microtubules, with binding saturation occurring with one MAP2 molecule per five to six tubulin dimers, as it does with mammalian microtubules. MAP2 binding and dissociation analyses revealed two affinity classes of binding sites on maize microtubules: a high-affinity site 12 dimers apart that may be homologous to the cognate mammalian MAP2 binding site and an additional low-affinity site also 12 dimers apart that may be homologous to the mammalian tau binding site. MAPS corrected in vitro folding errors in taxol-stabilized maize microtubules and reduced the critical concentration of maize tubulin polymerization eightfold, from 8.3 to 1.0 pM. However, MAPS dissociated much more readily from maize microtubules than from mammalian microtubules and induced the assembly of maize tubulin into aberrant helical ribbon polymers that remained stable for prolonged periods. Our results indicated that MAPS binds to maize tubulin via a partially specific, low-fidelity interaction that reflects unique structural and functional properties of the polymerization and regulatory domains of plant tubulin and possibly of the tubulin binding domains of undocumented MAPs that regulate microtubule function in plant cells.

show abstract

“…Tubulin was isolated from stationary phase cells of maize by DEAE-Sephadex A50 chromatography (Morejohn and Fosket, 1982), with certain modifications (Bokros et al, 1993). Quantitative densitometry of Coomassie blue-stained SDS-PAGE gels containing DEAE-tubulin fractions (Fig.…”

Section: General Characteristics Of Oryzalin Binding To Maize Tubulinmentioning

confidence: 99%

“…Maize tubulin was isolated from stationary phase (d 7-8) cells using DEAE-Sephadex A50 chromatography accoding to the method of Morejohn and Fosket (1982) with modifications as described by Bokros et al (1993). Ammoinium sulfate precipitates of DEAE-tubulin were resuspended i n an IB consisting of 50 m~ Pipes-KOH (pH 6.9), 1 m~ EGTA, 0.5 m~ MgS04, and 1 m~ DTT and supplemented with 0.1 m~ GTP, 50 p g mL-' Na-p-tosyl-L-Arg methyl ester, and 5 pg mL-' each of pepstatin A, leupeptin hemisulfate, and aprotinin.…”

Section: Lsolation and Purification Of Maize Tubulinmentioning

confidence: 99%

Rapid and Reversible High-Affinity Binding of the Dinitroaniline Herbicide Oryzalin to Tubulin from Zea mays L

1993

View full text Add to dashboard Cite

Higher plant tubulin identified by self-assembly into microtubules in vitro

Cited by 93 publications

References 35 publications

Light Regulation of β-Tubulin Gene Expression during Internode Development in Soybean (Glycine max [L.] Merr.)

Light Regulation of β-Tubulin Gene Expression during Internode Development in Soybean (Glycine max [L.] Merr.)

Unique functional characteristics of the polymerization and MAP binding regulatory domains of plant tubulin.

Rapid and Reversible High-Affinity Binding of the Dinitroaniline Herbicide Oryzalin to Tubulin from Zea mays L

Contact Info

Product

Resources

About