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AtTCTP2, an Arabidopsis thaliana homolog of Translationally Controlled Tumor Protein, enhances in vitro plant regeneration.

Toscano-Morales R, Xoconostle-Cázares B, Cabrera-Ponce JL, Hinojosa-Moya J, Ruiz-Salas JL, Galván-Gordillo SV, Guevara-González RG, Ruiz-Medrano R - Front Plant Sci (2015)

Bottom Line: AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants.Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency.This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Plant Molecular Biology, Department of Biotechnology and Bioengineering, CINVESTAV Mexico City, Mexico.

ABSTRACT
The Translationally Controlled Tumor Protein (TCTP) is a central regulator of cell proliferation and differentiation in animals, and probably also in plants. Arabidopsis harbors two TCTP genes, AtTCTP1 (At3g16640), which is an important mitotic regulator, and AtTCTP2 (At3g05540), which is considered a pseudogene. Nevertheless, we have obtained evidence suggesting that this gene is functional. Indeed, a T-DNA insertion mutant, SALK_045146, displays a lethal phenotype during early rosette stage. Also, both the AtTCTP2 promoter and structural gene are functional, and heterozygous plants show delayed development. AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants. Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency. Insertion of a sequence present in AtTCTP1 but absent in AtTCTP2 demonstrates that it suppresses the capacity for plant regeneration; also, this phenomenon is enhanced by the presence of TCTP (AtTCTP1 or 2) in the nuclei of root cells. This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species.

No MeSH data available.


Related in: MedlinePlus

Subcellular localization of AtTCTP2 and AtTCTP1 in regenerated tobacco plants. Tissue from regenerated plants harboring both unmodified and modified versions of AtTCTP2 and AtTCTP1 were analyzed by confocal laser-scanning microscopy. (A) AtTCTP2-GFP accumulates in stomata (insert: bottom-left) and nuclei (N, arrowheads) in leaves; (B) while in roots its signal was associated to nuclei and vascular tissue (N, arrowheads). (C) AtTCTP1-GFP also accumulates in stomata (insert: bottom-left) and nuclei in leaves, but not in (D) root nuclei. (E–F) Representative wild-type controls for leaf and root are shown. Bars = 25 μm.
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Figure 9: Subcellular localization of AtTCTP2 and AtTCTP1 in regenerated tobacco plants. Tissue from regenerated plants harboring both unmodified and modified versions of AtTCTP2 and AtTCTP1 were analyzed by confocal laser-scanning microscopy. (A) AtTCTP2-GFP accumulates in stomata (insert: bottom-left) and nuclei (N, arrowheads) in leaves; (B) while in roots its signal was associated to nuclei and vascular tissue (N, arrowheads). (C) AtTCTP1-GFP also accumulates in stomata (insert: bottom-left) and nuclei in leaves, but not in (D) root nuclei. (E–F) Representative wild-type controls for leaf and root are shown. Bars = 25 μm.

Mentions: Both Arabidopsis TCTPs showed stomatal and nuclear localization in leaves. However, AtTCTP2 was readily detected in the nuclei of root cortical cells of regenerated plants, in contrast to AtTCTP1 (Figures 9A–D). Furthermore, AtTCTP2:GFP fusions driven by the CaMV35S or its endogenous promoter accumulated in punctae in the cell periphery, reminiscent of non-cell autonomous proteins, such as NtNCAPP1 (Lee et al., 2003; Figure S6). In contrast, in the few cases in which AtTCTP1 could have induced regeneration, AtTCTP1-GFP fusions did not show such accumulation pattern, similar to the WT control (Figures 9C–F).


AtTCTP2, an Arabidopsis thaliana homolog of Translationally Controlled Tumor Protein, enhances in vitro plant regeneration.

Toscano-Morales R, Xoconostle-Cázares B, Cabrera-Ponce JL, Hinojosa-Moya J, Ruiz-Salas JL, Galván-Gordillo SV, Guevara-González RG, Ruiz-Medrano R - Front Plant Sci (2015)

Subcellular localization of AtTCTP2 and AtTCTP1 in regenerated tobacco plants. Tissue from regenerated plants harboring both unmodified and modified versions of AtTCTP2 and AtTCTP1 were analyzed by confocal laser-scanning microscopy. (A) AtTCTP2-GFP accumulates in stomata (insert: bottom-left) and nuclei (N, arrowheads) in leaves; (B) while in roots its signal was associated to nuclei and vascular tissue (N, arrowheads). (C) AtTCTP1-GFP also accumulates in stomata (insert: bottom-left) and nuclei in leaves, but not in (D) root nuclei. (E–F) Representative wild-type controls for leaf and root are shown. Bars = 25 μm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4489097&req=5

Figure 9: Subcellular localization of AtTCTP2 and AtTCTP1 in regenerated tobacco plants. Tissue from regenerated plants harboring both unmodified and modified versions of AtTCTP2 and AtTCTP1 were analyzed by confocal laser-scanning microscopy. (A) AtTCTP2-GFP accumulates in stomata (insert: bottom-left) and nuclei (N, arrowheads) in leaves; (B) while in roots its signal was associated to nuclei and vascular tissue (N, arrowheads). (C) AtTCTP1-GFP also accumulates in stomata (insert: bottom-left) and nuclei in leaves, but not in (D) root nuclei. (E–F) Representative wild-type controls for leaf and root are shown. Bars = 25 μm.
Mentions: Both Arabidopsis TCTPs showed stomatal and nuclear localization in leaves. However, AtTCTP2 was readily detected in the nuclei of root cortical cells of regenerated plants, in contrast to AtTCTP1 (Figures 9A–D). Furthermore, AtTCTP2:GFP fusions driven by the CaMV35S or its endogenous promoter accumulated in punctae in the cell periphery, reminiscent of non-cell autonomous proteins, such as NtNCAPP1 (Lee et al., 2003; Figure S6). In contrast, in the few cases in which AtTCTP1 could have induced regeneration, AtTCTP1-GFP fusions did not show such accumulation pattern, similar to the WT control (Figures 9C–F).

Bottom Line: AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants.Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency.This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Plant Molecular Biology, Department of Biotechnology and Bioengineering, CINVESTAV Mexico City, Mexico.

ABSTRACT
The Translationally Controlled Tumor Protein (TCTP) is a central regulator of cell proliferation and differentiation in animals, and probably also in plants. Arabidopsis harbors two TCTP genes, AtTCTP1 (At3g16640), which is an important mitotic regulator, and AtTCTP2 (At3g05540), which is considered a pseudogene. Nevertheless, we have obtained evidence suggesting that this gene is functional. Indeed, a T-DNA insertion mutant, SALK_045146, displays a lethal phenotype during early rosette stage. Also, both the AtTCTP2 promoter and structural gene are functional, and heterozygous plants show delayed development. AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants. Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency. Insertion of a sequence present in AtTCTP1 but absent in AtTCTP2 demonstrates that it suppresses the capacity for plant regeneration; also, this phenomenon is enhanced by the presence of TCTP (AtTCTP1 or 2) in the nuclei of root cells. This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species.

No MeSH data available.


Related in: MedlinePlus