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Characterization of the Sesbania rostrata phytochelatin synthase gene: alternative splicing and function of four isoforms.

Li AM, Yu BY, Chen FH, Gan HY, Yuan JG, Qiu R, Huang JC, Yang ZY, Xu ZF - Int J Mol Sci (2009)

Bottom Line: Southern blot and sequence analysis revealed that a single copy of the SrPCS gene occurs in the S. rostrata genome, and produces four different SrPCS mRNAs and proteins, SrPCS1-SrPCS4, by alternative splicing of the SrPCS pre-mRNA.The SrPCS1 and SrPCS3 proteins conferred Cd tolerance when expressed in yeast cells, whereas the SrPCS2 and SrPCS4 proteins, which lack the catalytic triad and the N-terminal domains, did not.These results suggested that SrPCS1 and SrPCS3 have potential applications in genetic engineering of plants for enhancing heavy metal tolerance and phytoremediation of contaminated soils.

View Article: PubMed Central - PubMed

Affiliation: Sun Yat-sen University, Guangzhou, China. lsahmp68@yahoo.com.cn

ABSTRACT
Phytochelatins (PCs) play an important role in detoxification of heavy metals in plants. PCs are synthesized from glutathione by phytochelatin synthase (PCS), a dipeptidyltransferase. Sesbania rostrata is a tropical legume plant that can tolerate high concentrations of Cd and Zn. In this study, the S. rostrata PCS gene (SrPCS) and cDNAs were isolated and characterized. Southern blot and sequence analysis revealed that a single copy of the SrPCS gene occurs in the S. rostrata genome, and produces four different SrPCS mRNAs and proteins, SrPCS1-SrPCS4, by alternative splicing of the SrPCS pre-mRNA. The SrPCS1 and SrPCS3 proteins conferred Cd tolerance when expressed in yeast cells, whereas the SrPCS2 and SrPCS4 proteins, which lack the catalytic triad and the N-terminal domains, did not. These results suggested that SrPCS1 and SrPCS3 have potential applications in genetic engineering of plants for enhancing heavy metal tolerance and phytoremediation of contaminated soils.

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Schematic comparison of PCS polypeptides from different plants.The positions of the conserved Cys residues are indicated by vertical bars. They exhibit at least 60% identical amino acids in pair-wise comparison. The triad Cys-56, His-162 and Asp-180 are indicated as asterisks. AtPCS1, PCS from A. thaliana, (GenBank accession no. AAD41794); LjPCS1, PCS from Lotus japonicus (GenBank accession no. AY633847); SrPCS1-4, PCS1-4 from S. rostrata (GenBank accession nos. DQ010916, GQ204308, GQ204309 and GQ204310).
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f1-ijms-10-03269: Schematic comparison of PCS polypeptides from different plants.The positions of the conserved Cys residues are indicated by vertical bars. They exhibit at least 60% identical amino acids in pair-wise comparison. The triad Cys-56, His-162 and Asp-180 are indicated as asterisks. AtPCS1, PCS from A. thaliana, (GenBank accession no. AAD41794); LjPCS1, PCS from Lotus japonicus (GenBank accession no. AY633847); SrPCS1-4, PCS1-4 from S. rostrata (GenBank accession nos. DQ010916, GQ204308, GQ204309 and GQ204310).

Mentions: Based on the conserved sequence of the known plant PCS proteins, four full-length cDNA clones encoding PCS in S. rostrata, designated SrPCS1 (GenBank accession no. DQ010916), SrPCS2 (GenBank accession no. GQ204308), SrPCS3 (GenBank accession no. GQ204309) and SrPCS4 (GenBank accession no. GQ204310), were isolated by RT-PCR amplification of conserved cDNA sequences combined with 3′ and 5′-rapid amplification of cDNA ends (RACE). The calculated molecular masses from the deduced amino acid sequences of SrPCS1, SrPCS2, SrPCS3 and SrPCS4 are 26 kD, 19.8 kD, 55.8 kD, and 19.9 kD, respectively (Figure 1).


Characterization of the Sesbania rostrata phytochelatin synthase gene: alternative splicing and function of four isoforms.

Li AM, Yu BY, Chen FH, Gan HY, Yuan JG, Qiu R, Huang JC, Yang ZY, Xu ZF - Int J Mol Sci (2009)

Schematic comparison of PCS polypeptides from different plants.The positions of the conserved Cys residues are indicated by vertical bars. They exhibit at least 60% identical amino acids in pair-wise comparison. The triad Cys-56, His-162 and Asp-180 are indicated as asterisks. AtPCS1, PCS from A. thaliana, (GenBank accession no. AAD41794); LjPCS1, PCS from Lotus japonicus (GenBank accession no. AY633847); SrPCS1-4, PCS1-4 from S. rostrata (GenBank accession nos. DQ010916, GQ204308, GQ204309 and GQ204310).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2812823&req=5

f1-ijms-10-03269: Schematic comparison of PCS polypeptides from different plants.The positions of the conserved Cys residues are indicated by vertical bars. They exhibit at least 60% identical amino acids in pair-wise comparison. The triad Cys-56, His-162 and Asp-180 are indicated as asterisks. AtPCS1, PCS from A. thaliana, (GenBank accession no. AAD41794); LjPCS1, PCS from Lotus japonicus (GenBank accession no. AY633847); SrPCS1-4, PCS1-4 from S. rostrata (GenBank accession nos. DQ010916, GQ204308, GQ204309 and GQ204310).
Mentions: Based on the conserved sequence of the known plant PCS proteins, four full-length cDNA clones encoding PCS in S. rostrata, designated SrPCS1 (GenBank accession no. DQ010916), SrPCS2 (GenBank accession no. GQ204308), SrPCS3 (GenBank accession no. GQ204309) and SrPCS4 (GenBank accession no. GQ204310), were isolated by RT-PCR amplification of conserved cDNA sequences combined with 3′ and 5′-rapid amplification of cDNA ends (RACE). The calculated molecular masses from the deduced amino acid sequences of SrPCS1, SrPCS2, SrPCS3 and SrPCS4 are 26 kD, 19.8 kD, 55.8 kD, and 19.9 kD, respectively (Figure 1).

Bottom Line: Southern blot and sequence analysis revealed that a single copy of the SrPCS gene occurs in the S. rostrata genome, and produces four different SrPCS mRNAs and proteins, SrPCS1-SrPCS4, by alternative splicing of the SrPCS pre-mRNA.The SrPCS1 and SrPCS3 proteins conferred Cd tolerance when expressed in yeast cells, whereas the SrPCS2 and SrPCS4 proteins, which lack the catalytic triad and the N-terminal domains, did not.These results suggested that SrPCS1 and SrPCS3 have potential applications in genetic engineering of plants for enhancing heavy metal tolerance and phytoremediation of contaminated soils.

View Article: PubMed Central - PubMed

Affiliation: Sun Yat-sen University, Guangzhou, China. lsahmp68@yahoo.com.cn

ABSTRACT
Phytochelatins (PCs) play an important role in detoxification of heavy metals in plants. PCs are synthesized from glutathione by phytochelatin synthase (PCS), a dipeptidyltransferase. Sesbania rostrata is a tropical legume plant that can tolerate high concentrations of Cd and Zn. In this study, the S. rostrata PCS gene (SrPCS) and cDNAs were isolated and characterized. Southern blot and sequence analysis revealed that a single copy of the SrPCS gene occurs in the S. rostrata genome, and produces four different SrPCS mRNAs and proteins, SrPCS1-SrPCS4, by alternative splicing of the SrPCS pre-mRNA. The SrPCS1 and SrPCS3 proteins conferred Cd tolerance when expressed in yeast cells, whereas the SrPCS2 and SrPCS4 proteins, which lack the catalytic triad and the N-terminal domains, did not. These results suggested that SrPCS1 and SrPCS3 have potential applications in genetic engineering of plants for enhancing heavy metal tolerance and phytoremediation of contaminated soils.

Show MeSH