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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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Chromosomal positions and duplication of genes in the AS2/LOB family in Arabidopsis. Gray bars and dark-gray ellipses show the chromosomes and the positions of centromeres, respectively. The chromosome number is given at the top of each chromosome. Black arrowheads next to the names of genes indicate the directions of transcription. White bars on the left of chromosomes indicate duplicated segments that contain pairs of putative duplicated genes in the AS2/LOB family. Each set of putative duplicated genes is shown in a single color. Solid and dashed lines link each set of duplicated genes, the genomic positions of whidch are encompassed by recently and old duplicated segments, respectively. Members of three pairs of ASL/LBD genes that are located next to one another are boxed. Members of groups 1, 2, 3, 4 and 8 that are considered to be sets of duplicated genes are shown in brown, orange, red, light blue and purple, respectively.
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fig03: Chromosomal positions and duplication of genes in the AS2/LOB family in Arabidopsis. Gray bars and dark-gray ellipses show the chromosomes and the positions of centromeres, respectively. The chromosome number is given at the top of each chromosome. Black arrowheads next to the names of genes indicate the directions of transcription. White bars on the left of chromosomes indicate duplicated segments that contain pairs of putative duplicated genes in the AS2/LOB family. Each set of putative duplicated genes is shown in a single color. Solid and dashed lines link each set of duplicated genes, the genomic positions of whidch are encompassed by recently and old duplicated segments, respectively. Members of three pairs of ASL/LBD genes that are located next to one another are boxed. Members of groups 1, 2, 3, 4 and 8 that are considered to be sets of duplicated genes are shown in brown, orange, red, light blue and purple, respectively.

Mentions: We investigated a possible relationship between the genetic divergence of members of the AS2/LOB family and duplication events in the Arabidopsis genome. We examined the chromosomal locations and the duplicated segments in which genes of the AS2/LOB family are found, using data from the Arabidopsis Genome Initiative (2000) and from the report by Blanc et al. (2003) (Figure 3). We found that the genes are distributed over all five chromosomes, with the exception of the short arm of chromosome II. Four sets of genes (ASL1/LBD36 and ASL25/LBD28; ASL7/LBD11 and ASL8/LBD1; ASL16/LBD29 and ASL18/LBD16; and ASL39/LBD37 and ASL40/LBD38) constitute pairs of duplicated genes in blocks of chromosomes that were duplicated approximately 24–40 million years ago. Four other pairs of genes (ASL1/LBD36 and ASL2/LBD10; ASL19/LBD30 and ASL20/LBD18; ASL39/LBD37 and ASL41/LBD39; and ASL40/LBD38 and ASL41/LBD39) constitute pairs of duplicated genes in the older blocks that were duplicated in the more distant past.


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)

Chromosomal positions and duplication of genes in the AS2/LOB family in Arabidopsis. Gray bars and dark-gray ellipses show the chromosomes and the positions of centromeres, respectively. The chromosome number is given at the top of each chromosome. Black arrowheads next to the names of genes indicate the directions of transcription. White bars on the left of chromosomes indicate duplicated segments that contain pairs of putative duplicated genes in the AS2/LOB family. Each set of putative duplicated genes is shown in a single color. Solid and dashed lines link each set of duplicated genes, the genomic positions of whidch are encompassed by recently and old duplicated segments, respectively. Members of three pairs of ASL/LBD genes that are located next to one another are boxed. Members of groups 1, 2, 3, 4 and 8 that are considered to be sets of duplicated genes are shown in brown, orange, red, light blue and purple, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig03: Chromosomal positions and duplication of genes in the AS2/LOB family in Arabidopsis. Gray bars and dark-gray ellipses show the chromosomes and the positions of centromeres, respectively. The chromosome number is given at the top of each chromosome. Black arrowheads next to the names of genes indicate the directions of transcription. White bars on the left of chromosomes indicate duplicated segments that contain pairs of putative duplicated genes in the AS2/LOB family. Each set of putative duplicated genes is shown in a single color. Solid and dashed lines link each set of duplicated genes, the genomic positions of whidch are encompassed by recently and old duplicated segments, respectively. Members of three pairs of ASL/LBD genes that are located next to one another are boxed. Members of groups 1, 2, 3, 4 and 8 that are considered to be sets of duplicated genes are shown in brown, orange, red, light blue and purple, respectively.
Mentions: We investigated a possible relationship between the genetic divergence of members of the AS2/LOB family and duplication events in the Arabidopsis genome. We examined the chromosomal locations and the duplicated segments in which genes of the AS2/LOB family are found, using data from the Arabidopsis Genome Initiative (2000) and from the report by Blanc et al. (2003) (Figure 3). We found that the genes are distributed over all five chromosomes, with the exception of the short arm of chromosome II. Four sets of genes (ASL1/LBD36 and ASL25/LBD28; ASL7/LBD11 and ASL8/LBD1; ASL16/LBD29 and ASL18/LBD16; and ASL39/LBD37 and ASL40/LBD38) constitute pairs of duplicated genes in blocks of chromosomes that were duplicated approximately 24–40 million years ago. Four other pairs of genes (ASL1/LBD36 and ASL2/LBD10; ASL19/LBD30 and ASL20/LBD18; ASL39/LBD37 and ASL41/LBD39; and ASL40/LBD38 and ASL41/LBD39) constitute pairs of duplicated genes in the older blocks that were duplicated in the more distant past.

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
Related in: MedlinePlus