Differential Expansion and Expression ofα- andβ-Tubulin Gene Families inPopulus 

Abstract

Microtubule organization is intimately associated with cellulose microfibril deposition, central to plant secondary cell wall development. We have determined that a relatively large suite of eight a-TUBULIN (TUA) and 20 b-TUBULIN (TUB) genes is expressed in the woody perennial Populus. A number of features, including gene number, a:b gene representation, amino acid changes at the C terminus, and transcript abundance in wood-forming tissue, distinguish the Populus tubulin suite from that of Arabidopsis thaliana. Five of the eight Populus TUAs are unusual in that they contain a C-terminal methionine, glutamic acid, or glutamine, instead of the more typical, and potentially regulatory, C-terminal tyrosine. Both C-terminal Y-type (TUA1) and M-type (TUA5) TUAs were highly expressed in wood-forming tissues and pollen, while the Y-type TUA6 and TUA8 were abundant only in pollen. Transcripts of the disproportionately expanded TUB family were present at comparatively low levels, with phylogenetically distinct classes predominating in xylem and pollen. When tension wood induction was used as a model system to examine changes in tubulin gene expression under conditions of augmented cellulose deposition, xylem-abundant TUA and TUB genes were up-regulated. Immunolocalization of TUA and TUB in xylem and phloem fibers of stems further supported the notion of heavy microtubule involvement during cellulose microfibril deposition in secondary walls. The high degree of sequence diversity, differential expansion, and differential regulation of Populus TUA and TUB families may confer flexibility in cell wall formation that is of adaptive significance to the woody perennial growth habit.

Association Genetics of Wood Physical Traits in the Conifer White Spruce and Relationships With Gene Expression

“…Tubulins (TUA2 and TUB3): Several lines of evidence suggest that the xylem predominant TUA and TUB isoforms are specifically associated with cellulose synthesis during secondary cell wall formation (Oakley et al 2007). Both of the P. glauca tubulins were expressed preferentially in xylem and shared sequenced homologies with tubulins from P. taeda that are highly abundant among ESTs from xylem cDNA libraries (Yang et al 2004) and SAGE sequencing data (Lorenz and Dean 2002).…”

Formación De Elementos Anatómicos en Maderas Duras: Una Revisión Desde Una Perspectiva Genómica

“…Ese comportamiento es influenciado por factores temporales y espaciales que afectan la concentración de TUA y TUB dentro del citoplasma (Spokevicius et al 2007). Oakley et al (2007) analizaron los patrones de expresión de los transcritos de tua y tub en diferentes tejidos de Populus a través de qRT-PCR, utilizando primers específicos para ocho genes tua y 20 genes tub. Ellos observaron que en el xilema de Populus, tres genes tua se expresaron en comparación al gran número de genes tub detectado, sin embargo, los niveles de expresión de los genes tua fueron mayores.…”

“…Otros estudios evidencian que las isoformas de TUA y TUB predominantes en el xilema están asociadas a la síntesis de celulosa durante la formación de la pared celular secundaria, probablemente influyendo en el control que ejercen los microtúbulos sobre el complejo enzimático de CesA (Bhandari et al 2006, Oakley et al 2007, Spokevicius et al 2007. El primero se refiere a la inmunolocalización de las proteínas de TUA y TUB encontradas en las fibras de xilema y floema que depositan su pared celular secundaria.…”

Identification of an Alpha-Tubulin Gene from the Chinese Mitten Crab Eriocheir sinensis: Expression Profiles under Immune Challenge and during Larval Development

“…In this study we have cloned the full-length cDNA of EsTUBA from E. sinensis and examined expression profiles in association with larval development and immune challenge stress. Due to association of α-tubulin with cell division [9,11] and immunoprotection [25], studies on the expression regulation of this gene would be critical to understand its role during the brachyurization development and immune challenge stress in the economically important crabs.…”

“…Tubulins as important component of the MTs in the cytoskeleton have been well known for a long time [5][6][7][8]. The tubulin family builds the MTs that play highly diverse and essential roles in eukaryotic cells, including cell division and elongation [9][10][11], maintaining cell structure [9,12], vesicle transport [11], signal transduction [4], etc. During the last decade, many studies on the structure and function of tubulins and their interaction with other proteins have been reported [8,13].…”