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A cytoplasm-specific activity encoded by the Trithorax-like ATX1 gene.

Ndamukong I, Lapko H, Cerny RL, Avramova Z - Nucleic Acids Res. (2011)

Bottom Line: It is encoded from an internal promoter in the ATX1 locus as an isoform containing only the SET domain (soloSET).It is located exclusively in the cytoplasm and its substrate is the elongation factor 1A (EF1A).Loss of SET, but not of the histone modifying ATX1-SET activity, affects cytoskeletal actin bundling illustrating that the two isoforms have distinct functions in Arabidopsis cells.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA.

ABSTRACT
Eukaryotes produce multiple products from a single gene locus by alternative splicing, translation or promoter usage as mechanisms expanding the complexity of their proteome. Trithorax proteins, including the Arabidopsis Trithorax-like protein ATX1, are histone modifiers regulating gene activity. Here, we report that a novel member of the Trithorax family has a role unrelated to chromatin. It is encoded from an internal promoter in the ATX1 locus as an isoform containing only the SET domain (soloSET). It is located exclusively in the cytoplasm and its substrate is the elongation factor 1A (EF1A). Loss of SET, but not of the histone modifying ATX1-SET activity, affects cytoskeletal actin bundling illustrating that the two isoforms have distinct functions in Arabidopsis cells.

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Related in: MedlinePlus

Transcripts produced from the ATX1 locus in RNAi- SET transformed plants. (a) RT–PCR analysis of ATX1 specific transcripts. The peptide domains encoded by the tested regions are shown to the right of the panels. Numbers of top of lanes indicate independently transformed lines tested for expression of ATX1 and its derivatives. As controls, all primers were tested for the specific fragment amplification in wild-type leaf (L) and flower (F) tissues. SET domain transcripts detected in all transgenic lines are shown in the panel indicated as SET. Transcripts from upstream ATX1 regions were not detected, except for weak bands corresponding to the Tu-PWWP and DAST regions in line 4. (b) Positioning of the primers used to amplify specific regions and of the produced transcripts are illustrated.
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Figure 3: Transcripts produced from the ATX1 locus in RNAi- SET transformed plants. (a) RT–PCR analysis of ATX1 specific transcripts. The peptide domains encoded by the tested regions are shown to the right of the panels. Numbers of top of lanes indicate independently transformed lines tested for expression of ATX1 and its derivatives. As controls, all primers were tested for the specific fragment amplification in wild-type leaf (L) and flower (F) tissues. SET domain transcripts detected in all transgenic lines are shown in the panel indicated as SET. Transcripts from upstream ATX1 regions were not detected, except for weak bands corresponding to the Tu-PWWP and DAST regions in line 4. (b) Positioning of the primers used to amplify specific regions and of the produced transcripts are illustrated.

Mentions: First, we asked whether RNAi-SET affected the levels of ATX1 and/or soloSET transcripts. Using primers overlapping various regions of the ATX1 gene, we show the results from six independently transformed lines analyzed by RT–PCR (Figure 3a and b). As expected, the primers failed to amplify all regions in the ATX1 mRNA, except at the 3′-end. An exception was line 4 where weak bands were detected from amplification of regions upstream of the Ti-insertion. Most unexpected, however, was the recovery of the SET-domain sequences from all transgenic samples indicating that SET domain transcripts were produced in all RNAi-SET lines (Figure 3a). These results indicated that production of ATX1 transcripts was knocked down in the presence of RNAi-SET, while transcripts from its SET-domain region (soloSET) were not substantially decreased.Figure 3.


A cytoplasm-specific activity encoded by the Trithorax-like ATX1 gene.

Ndamukong I, Lapko H, Cerny RL, Avramova Z - Nucleic Acids Res. (2011)

Transcripts produced from the ATX1 locus in RNAi- SET transformed plants. (a) RT–PCR analysis of ATX1 specific transcripts. The peptide domains encoded by the tested regions are shown to the right of the panels. Numbers of top of lanes indicate independently transformed lines tested for expression of ATX1 and its derivatives. As controls, all primers were tested for the specific fragment amplification in wild-type leaf (L) and flower (F) tissues. SET domain transcripts detected in all transgenic lines are shown in the panel indicated as SET. Transcripts from upstream ATX1 regions were not detected, except for weak bands corresponding to the Tu-PWWP and DAST regions in line 4. (b) Positioning of the primers used to amplify specific regions and of the produced transcripts are illustrated.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3113559&req=5

Figure 3: Transcripts produced from the ATX1 locus in RNAi- SET transformed plants. (a) RT–PCR analysis of ATX1 specific transcripts. The peptide domains encoded by the tested regions are shown to the right of the panels. Numbers of top of lanes indicate independently transformed lines tested for expression of ATX1 and its derivatives. As controls, all primers were tested for the specific fragment amplification in wild-type leaf (L) and flower (F) tissues. SET domain transcripts detected in all transgenic lines are shown in the panel indicated as SET. Transcripts from upstream ATX1 regions were not detected, except for weak bands corresponding to the Tu-PWWP and DAST regions in line 4. (b) Positioning of the primers used to amplify specific regions and of the produced transcripts are illustrated.
Mentions: First, we asked whether RNAi-SET affected the levels of ATX1 and/or soloSET transcripts. Using primers overlapping various regions of the ATX1 gene, we show the results from six independently transformed lines analyzed by RT–PCR (Figure 3a and b). As expected, the primers failed to amplify all regions in the ATX1 mRNA, except at the 3′-end. An exception was line 4 where weak bands were detected from amplification of regions upstream of the Ti-insertion. Most unexpected, however, was the recovery of the SET-domain sequences from all transgenic samples indicating that SET domain transcripts were produced in all RNAi-SET lines (Figure 3a). These results indicated that production of ATX1 transcripts was knocked down in the presence of RNAi-SET, while transcripts from its SET-domain region (soloSET) were not substantially decreased.Figure 3.

Bottom Line: It is encoded from an internal promoter in the ATX1 locus as an isoform containing only the SET domain (soloSET).It is located exclusively in the cytoplasm and its substrate is the elongation factor 1A (EF1A).Loss of SET, but not of the histone modifying ATX1-SET activity, affects cytoskeletal actin bundling illustrating that the two isoforms have distinct functions in Arabidopsis cells.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA.

ABSTRACT
Eukaryotes produce multiple products from a single gene locus by alternative splicing, translation or promoter usage as mechanisms expanding the complexity of their proteome. Trithorax proteins, including the Arabidopsis Trithorax-like protein ATX1, are histone modifiers regulating gene activity. Here, we report that a novel member of the Trithorax family has a role unrelated to chromatin. It is encoded from an internal promoter in the ATX1 locus as an isoform containing only the SET domain (soloSET). It is located exclusively in the cytoplasm and its substrate is the elongation factor 1A (EF1A). Loss of SET, but not of the histone modifying ATX1-SET activity, affects cytoskeletal actin bundling illustrating that the two isoforms have distinct functions in Arabidopsis cells.

Show MeSH
Related in: MedlinePlus