Domains of the TMV movement protein involved in subcellular localization

Abstract

SummaryTo identify and map functionally important regions of the tobacco mosaic virus movement protein, deletions of three amino acids were introduced at intervals of 10 amino acids throughout the protein. Mutations located between amino acids 1 and 160 abolished the capacity of the protein to transport virus from cell to cell, while some of the mutations in the C-terminal third of the protein permitted function. Despite extensive tests, no examples were found of intermolecular complementation between mutants, suggesting that function requires each movement protein molecule to be fully competent. Many of the mutants were fused to green fluorescent protein, and their subcellular localizations were determined by fluorescence microscopy in infected plants and protoplasts. Most mutants lost the ability to accumulate in one or more of the multiple subcellular sites targeted by wild-type movement protein, suggesting that specific functional domains were disrupted. The order in which accumulation at subcellular sites occurs during infection does not represent a targeting pathway. Association of the movement protein with microtubules or with plasmodesmata can occur in the absence of other associations. The region of the protein around amino acids 9-11 may be involved in targeting the protein to cortical bodies (probably associated with the endoplasmic reticulum) and to plasmodesmata. The region around residues 49-51 may be involved in co-alignment of the protein with microtubules. The region around residues 88-101 appears to play a role in targeting to both the cortical bodies and microtubules. Thus, the movement protein contains independently functional domains.

MPB2C, a Microtubule-Associated Plant Protein Binds to and Interferes with Cell-to-Cell Transport of Tobacco Mosaic Virus Movement Protein

“…In line, the filament and body-like appearance of MPB2C resembles described intracellular localization patterns of MP30 (Heinlein et al, 1995McLean et al, 1995;Kahn et al, 1998;Mas and Beachy, 1999;Crawford and Zambryski, 2000;Boyko et al, 2000aBoyko et al, , 2000bKotlizky et al, 2001).…”

Structural Properties of Carnation Mottle Virus p7 Movement Protein and Its RNA-binding Domain

“…In order to confirm that the previously described RNA-binding peptide (29) corresponds to the binding domain of p7, this peptide (p7 [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] ) and two additional peptides (p7 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and p7 40 -61 ) derived from the primary sequence of p7 (Fig. 1A) were synthesized and assayed for RNA binding.…”

“…29, except for peptide p7 [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] , which was obtained from DiverDrugs (Barcelona, Spain). Analytical RP-HPLC and laser desorption time-of-flight mass spectrometry were used to determine the purity and identity of the peptides.…”

“…The 30-kDa TMV MP binds single-stranded (viral) RNA in vitro with no sequence specificity and high cooperativity (5), co-localizes with the cytoskeleton and cell wall (6 -8), is required for the association of viral RNA with endoplasmic reticulum (9), increases the size exclusion limit of plasmodesmata (10), and mediates an active transport of the viral genome to the adjacent cell (4). Sequence deletion and mutagenesis studies have located some of these functions in separate motifs/domains of the protein (11)(12)(13). These properties define the tobamo-like model of viral cell transport.…”

Binding of monoclonal antibodies to the movement protein (MP) of Tobacco mosaic virus: influence of subcellular MP localization and phosphorylation

“…The functional domains of TMV MP have been investigated by Berna et al (1991), Gafny et al (1992), Citovsky et al (1992), Waigmann et al (1994) and Kahn et al (1998). The hypothesis that MP contains two transmembrane domains (Berna, 1995) was supported by studies using recombinant MP (Brill et al, 2000(Brill et al, , 2004.…”