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Characterization of genes in the ASYMMETRIC LEAVES2/LATERAL ORGAN BOUNDARIES (AS2/LOB) family in Arabidopsis thaliana, and functional and molecular comparisons between AS2 and other family members.

Matsumura Y, Iwakawa H, Machida Y, Machida C - Plant J. (2009)

Bottom Line: Comparisons among amino acid sequences that had been deduced from the cloned cDNAs revealed eight groups of genes, with two or three members each, and high degrees of identity among entire amino acid sequences, suggesting that some members of the AS2/LOB family might have redundant function(s).Moreover, no member of the family exhibited significant similarity, in terms of the deduced amino acid sequence of the carboxy-terminal half, to AS2.Results of domain swapping between AS2 and other members of the family showed that the AS2/LOB domain of AS2 cannot be functionally replaced by those of other members of the family, and that only a few dissimilarities among respective amino acid residues of the AS2/LOB domain of AS2 and those of other members are important for the specific functions of AS2.

View Article: PubMed Central - PubMed

Affiliation: Plant Biology Research Center, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.

ABSTRACT
The ASYMMETRIC LEAVES2 (AS2) gene is required for the generation of the flat and symmetrical shape of the leaf lamina in Arabidopsis. AS2 encodes a plant-specific protein with an AS2/LATERAL ORGAN BOUNDARIES (AS2/LOB) domain that includes a cysteine repeat, a conserved single glycine residue and a leucine-zipper-like sequence in its amino-terminal half. The Arabidopsis genome contains 42 genes, including AS2, that encode proteins with an AS2/LOB domain in their amino-terminal halves, and these genes constitute the AS2/LOB gene family. In the present study, we cloned and characterized cDNAs that covered the putative coding regions of all members of this family, and investigated patterns of transcription systematically in Arabidopsis plants. Comparisons among amino acid sequences that had been deduced from the cloned cDNAs revealed eight groups of genes, with two or three members each, and high degrees of identity among entire amino acid sequences, suggesting that some members of the AS2/LOB family might have redundant function(s). Moreover, no member of the family exhibited significant similarity, in terms of the deduced amino acid sequence of the carboxy-terminal half, to AS2. Results of domain swapping between AS2 and other members of the family showed that the AS2/LOB domain of AS2 cannot be functionally replaced by those of other members of the family, and that only a few dissimilarities among respective amino acid residues of the AS2/LOB domain of AS2 and those of other members are important for the specific functions of AS2.

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Schematic representations of ASL/LBD genes. (a) The exon–intron organization of 17 newly identified ASL/LBD genes, and that of ASL15/LBD17. Boxes and lines indicate the exons and introns, respectively, that were deduced from genomic and cDNA sequences. Open and filled (gray and black) boxes represent untranslated and translated regions, respectively. The regions corresponding to AS2/LOB domains are indicated by black boxes. (b) The five subtypes of genes in the AS2/LOB family, based on positions of introns in coding regions. Filled (gray and black) boxes and open triangles indicate coding regions and positions of introns, respectively. Black boxes show the regions that correspond to AS2/LOB domains. ASL/LBD genes with no introns in their coding regions are not shown.
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fig01: Schematic representations of ASL/LBD genes. (a) The exon–intron organization of 17 newly identified ASL/LBD genes, and that of ASL15/LBD17. Boxes and lines indicate the exons and introns, respectively, that were deduced from genomic and cDNA sequences. Open and filled (gray and black) boxes represent untranslated and translated regions, respectively. The regions corresponding to AS2/LOB domains are indicated by black boxes. (b) The five subtypes of genes in the AS2/LOB family, based on positions of introns in coding regions. Filled (gray and black) boxes and open triangles indicate coding regions and positions of introns, respectively. Black boxes show the regions that correspond to AS2/LOB domains. ASL/LBD genes with no introns in their coding regions are not shown.

Mentions: The nucleotide sequences of the cDNAs for the 25 genes that had previously been submitted to the databases were identical to the sequences determined in the present study. However, the cDNA for ASL15/LBD17 that we cloned extended to a further-upstream region, and included a previously unidentified methionine codon, indicating that the predicted initiation codon of the ASL15/LBD17 gene is located 171 bp upstream of that of the previously characterized gene. Figure 1a shows the gene organization of the 17 newly characterized members of the family and ASL15/LBD17.


Characterization of genes in the ASYMMETRIC LEAVES2/LATERAL ORGAN BOUNDARIES (AS2/LOB) family in Arabidopsis thaliana, and functional and molecular comparisons between AS2 and other family members.

Matsumura Y, Iwakawa H, Machida Y, Machida C - Plant J. (2009)

Schematic representations of ASL/LBD genes. (a) The exon–intron organization of 17 newly identified ASL/LBD genes, and that of ASL15/LBD17. Boxes and lines indicate the exons and introns, respectively, that were deduced from genomic and cDNA sequences. Open and filled (gray and black) boxes represent untranslated and translated regions, respectively. The regions corresponding to AS2/LOB domains are indicated by black boxes. (b) The five subtypes of genes in the AS2/LOB family, based on positions of introns in coding regions. Filled (gray and black) boxes and open triangles indicate coding regions and positions of introns, respectively. Black boxes show the regions that correspond to AS2/LOB domains. ASL/LBD genes with no introns in their coding regions are not shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2721968&req=5

fig01: Schematic representations of ASL/LBD genes. (a) The exon–intron organization of 17 newly identified ASL/LBD genes, and that of ASL15/LBD17. Boxes and lines indicate the exons and introns, respectively, that were deduced from genomic and cDNA sequences. Open and filled (gray and black) boxes represent untranslated and translated regions, respectively. The regions corresponding to AS2/LOB domains are indicated by black boxes. (b) The five subtypes of genes in the AS2/LOB family, based on positions of introns in coding regions. Filled (gray and black) boxes and open triangles indicate coding regions and positions of introns, respectively. Black boxes show the regions that correspond to AS2/LOB domains. ASL/LBD genes with no introns in their coding regions are not shown.
Mentions: The nucleotide sequences of the cDNAs for the 25 genes that had previously been submitted to the databases were identical to the sequences determined in the present study. However, the cDNA for ASL15/LBD17 that we cloned extended to a further-upstream region, and included a previously unidentified methionine codon, indicating that the predicted initiation codon of the ASL15/LBD17 gene is located 171 bp upstream of that of the previously characterized gene. Figure 1a shows the gene organization of the 17 newly characterized members of the family and ASL15/LBD17.

Bottom Line: Comparisons among amino acid sequences that had been deduced from the cloned cDNAs revealed eight groups of genes, with two or three members each, and high degrees of identity among entire amino acid sequences, suggesting that some members of the AS2/LOB family might have redundant function(s).Moreover, no member of the family exhibited significant similarity, in terms of the deduced amino acid sequence of the carboxy-terminal half, to AS2.Results of domain swapping between AS2 and other members of the family showed that the AS2/LOB domain of AS2 cannot be functionally replaced by those of other members of the family, and that only a few dissimilarities among respective amino acid residues of the AS2/LOB domain of AS2 and those of other members are important for the specific functions of AS2.

View Article: PubMed Central - PubMed

Affiliation: Plant Biology Research Center, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.

ABSTRACT
The ASYMMETRIC LEAVES2 (AS2) gene is required for the generation of the flat and symmetrical shape of the leaf lamina in Arabidopsis. AS2 encodes a plant-specific protein with an AS2/LATERAL ORGAN BOUNDARIES (AS2/LOB) domain that includes a cysteine repeat, a conserved single glycine residue and a leucine-zipper-like sequence in its amino-terminal half. The Arabidopsis genome contains 42 genes, including AS2, that encode proteins with an AS2/LOB domain in their amino-terminal halves, and these genes constitute the AS2/LOB gene family. In the present study, we cloned and characterized cDNAs that covered the putative coding regions of all members of this family, and investigated patterns of transcription systematically in Arabidopsis plants. Comparisons among amino acid sequences that had been deduced from the cloned cDNAs revealed eight groups of genes, with two or three members each, and high degrees of identity among entire amino acid sequences, suggesting that some members of the AS2/LOB family might have redundant function(s). Moreover, no member of the family exhibited significant similarity, in terms of the deduced amino acid sequence of the carboxy-terminal half, to AS2. Results of domain swapping between AS2 and other members of the family showed that the AS2/LOB domain of AS2 cannot be functionally replaced by those of other members of the family, and that only a few dissimilarities among respective amino acid residues of the AS2/LOB domain of AS2 and those of other members are important for the specific functions of AS2.

Show MeSH