| Gene Information | |
| NCBI Gene ID | 844323 |
| Symbol | GL2 |
| LocusTag | AT1G79840 |
| Synonyms | F19K16.20|F19K16_20|GLABRA 2|HOMEOBOX PROTEIN GLABRA 2 |
| Description | GL2 (GLABRA 2); DNA binding / transcription factor |
| Gene Type | protein-coding |
| Pattern | GL2|AT1G79840|F19K16.20|F19K16_20|GLABRA 2|HOMEOBOX PROTEIN GLABRA 2|GL2 (GLABRA 2); DNA binding / transcription factor |
| Corresponding sequence in Trichome EST library | AI896332 AM793294 AM816471 AM821990 AM846667 BG124295 BI312112 BP884889 CN743658 CN746752 DB717947 DQ198166 EH368633 EH368668 EH368708 EH368749 EH371136 EY080767 EY080768 GD252362 TCHL58460 |
| Reference |
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Cellular differentiation in the leaf. Langdale JA. Curr Opin Cell Biol. 1998 Dec;10(6):734-8. ...... in the leaf. It has been suggested that a common developmental pathway involving MYB-like transcription factors is responsible for distinguishing between cellular identities in the epidermis and that nuclear-cytoplasmic partitioning of the GLABRA2 homeodomain protein plays a role in determining trichome cell fate. With respect to the differentiation of subepidermal cell types, molecular links have been made between auxin physiology and vascular development, and between plastid ...... |
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Control of GL2 expression in Arabidopsis leaves and trichomes. Szymanski DB, Jilk RA, Pollock SM, Marks MD. Development. 1998 Apr;125(7):1161-71. ...... are required for the correct initiation, spacing, and morphogenesis of trichomes in Arabidopsis. The initial selection of trichome precursors requires the activity of both the GLABROUS1 (GL1) and TRANSPARENT TESTA GLABROUS (TTG) genes. The GLABRA2 (GL2) gene is required for subsequent phases of trichome morphogenesis such as cell expansion, branching, and maturation of the trichome cell wall. Previous studies have shown that GL2 is a member of the homeodomain class of transcription ...... |
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...... fused to the GL2 promoter. The GL2 expression profile in the shoot is complex, and involves spatial and temporal variation in developing leaves and trichomes. Two separate promoter domains that are expressed in trichomes were identified. GL2, like GL1, is expressed in developing trichomes and in cells surrounding trichomes during early stages of trichome development. Unlike GL1, GL2 expression persists in mature trichomes. It was found that while GL1 and TTG were not required ...... |
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...... the initiation of GL2 expression in the non-trichome cells, the presence of a functional GL1 or TTG gene was able to increase GL2 expression in these cells compared to ttg gl1 plants. The hypothesis that GL1 regulates aspects of GL2 expression is consistent with epistatic analysis of gl1 and gl2 and the expression patterns of GL1 and GL2. In support of this hypothesis, it was found that ectopic expression of GL1 in the presence of ectopic expression of the maize R ...... |
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Epidermal cell differentiation in Arabidopsis determined by a Myb homolog, CPC. Wada T, Tachibana T, Shimura Y, Okada K. Science. 1997 Aug 22;277(5329):1113-6. ...... with a Myb-like DNA binding domain typical of transcription factors involved in animal and plant development. Analysis in combination with other root hair mutations showed that CPC may work together with the TTG gene and upstream of the GL2 gene. Transgenic plants overexpressing CPC had more root hairs and fewer trichomes than normal. Thus, the CPC gene determines the fate of epidermal cell differentiation in Arabidopsis. ...... |
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The Arabidopsis Athb-10 (GLABRA2) is an HD-Zip protein required for regulation of root hair development. Di Cristina M, Sessa G, Dolan L, Linstead P, Baima S, Ruberti I, Morelli G. Plant J. 1996 Sep;10(3):393-402. ...... indicate that, although less conserved, the leucine zipper of Athb-10 can functionally replace that of Athb-2 in an in vitro DNA-binding assay. Gene mapping experiments and sequence comparison analysis revealed that Athb-10 corresponds to GLABRA2, a homeodomain protein involved in trichome development. The mRNA expression analysis revealed that Athb-10/GLABRA2 is expressed not only in trichome-bearing organs, but also in the root. The analysis of wild-type and mutant plants showed ...... |
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The GLABRA2 gene encodes a homeo domain protein required for normal trichome development in Arabidopsis. Rerie WG, Feldmann KA, Marks MD. Genes Dev. 1994 Jun 15;8(12):1388-99. ...... The GLABRA2 gene (GL2) is one of several genes known to have a role in trichome development in Arabidopsis. Mutations at this locus result in abnormal trichome expansion. We have identified several gl2 mutants from a T-DNA-mutagenized population of ...... |
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...... homeo box genes in plants. The expression pattern of GL2, as demonstrated by in situ hybridization, indicated that the gene is expressed in trichome progenitor cells and at stages associated with trichome development. This suggests that GL2 may regulate events required for the directional cell expansion observed during trichome formation. ...... |
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Arabidopsis transient expression analysis reveals that activation of GLABRA2 may require concurrent binding of GLABRA1 and GLABRA3 to the promoter of GLABRA2. Wang S, Chen JG. Plant Cell Physiol. 2008 Dec;49(12):1792-804. Epub 2008 Oct 22 ...... MYB transcription factor, GLABRA3 (GL3), a basic helix-loop-helix (bHLH) transcription factor, and TRANSPARENT TESTA GLABRA1 (TTG1), a WD40 protein, are believed to form a transcriptional activator complex to control the transcription of GLABRA2 (GL2), which in turn induces trichome formation in shoots. However, the molecular mechanism of the regulation of GL2 expression by this activator complex is still poorly understood. Here we report that GL1 and GL3 control GL2 expression ...... |
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SAD2 in Arabidopsis functions in trichome initiation through mediating GL3 function and regulating GL1, TTG1 and GL2 expression. Gao Y, Gong X, Cao W, Zhao J, Fu L, Wang X, Schumaker KS, Guo Y. J Integr Plant Biol. 2008 Jul;50(7):906-17 ...... Most genes identified that control Arabidopsis trichome initiation and formation are transcription factors or regulatory components in transcriptional networks and include GLABROUS1 (GL1), GLABRA2 (GL2), GLABRA3 (GL3) and TRANSPARENT TESTA GLABRA1 (TTG1). Herein, we report that an importin beta-like protein, SENSITIVE TO ABA AND DROUGHT2 (SAD2), is required for trichome initiation. Mutations in SAD2 disrupted trichome initiation ...... |
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The HD-Zip IV gene GaHOX1 from cotton is a functional homologue of the Arabidopsis GLABRA2. Guan XY, Li QJ, Shan CM, Wang S, Mao YB, Wang LJ, Chen XY. Physiol Plant. 2008 Sep;134(1):174-82. Epub 2008 Apr 11 ...... Most of the plant homeodomain-containing proteins play important roles in organ patterning and development, and Arabidopsis GLABRA2 (GL2), a member of the class IV homeodomain-leucine zipper (HD-ZIP) proteins, is a trichome and non-root hair cell regulator. Here we report the analysis of two cotton homeodomain-containing proteins, GaHOX1 and GaHOX2, isolated from ...... |
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...... diploid cotton Gossypium arboreum. Both GaHOX1 and GaHOX2 belong to the class IV HD-ZIP family. When expressed under the control of the GL2 promoter, GaHOX1 rescued trichome development of an Arabidopsis glabrous mutant of gl2-2 (SALK_130213), whereas GaHOX2 did not. On the other hand, expression of GaHOX1 with a Cauliflower mosaic virus (CaMV) 35S promoter in the wild-type Arabidopsis plants suppressed the trichome development just as the GL2 ectopic ...... |
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...... consistent with its putative role in regulating cotton fiber development, while GaHOX2 is expressed in both fiber and other ovular tissues, including outer and inner integuments. Our results suggest that GaHOX1 is a functional homolog of GL2 in plant trichome development. ...... |
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Arabidopsis TRANSPARENT TESTA GLABRA2 is directly regulated by R2R3 MYB transcription factors and is involved in regulation of GLABRA2 transcription in epidermal differentiation. Ishida T, Hattori S, Sano R, Inoue K, Shirano Y, Hayashi H, Shibata D, Sato S, Kato T, Tabata S, Okada K, Wada T. Plant Cell. 2007 Aug;19(8):2531-43. ...... Arabidopsis thaliana TRANSPARENT TESTA GLABRA2 (TTG2) encodes a WRKY transcription factor and is expressed in young leaves, trichomes, seed coats, and root hairless cells. An examination of several trichome and root hair mutants indicates that MYB and bHLH genes regulate TTG2 ...... |
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...... pigmentation. Transgenic plants expressing a chimeric repressor version of the TTG2 protein (TTG2:SRDX) showed defects in trichome formation, anthocyanin accumulation, seed color pigmentation, and differentiation of root hairless cells. GLABRA2 (GL2) expression was markedly reduced in roots of ProTTG2:TTG2:SRDX transgenic plants, suggesting that TTG2 is involved in the regulation of GL2 expression, although GL2 expression in the ttg2 mutant was similar to that in the wild type. ...... |
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...... analysis suggests a new step in a regulatory cascade of epidermal differentiation, in which complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, which then regulates GL2 expression with complexes containing R2R3 MYB and bHLH in the differentiation of trichomes and root hairless cells. ...... |
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The homeobox gene GLABRA2 affects seed oil content in Arabidopsis. Shen B, Sinkevicius KW, Selinger DA, Tarczynski MC. Plant Mol Biol. 2006 Feb;60(3):377-87. ...... and one high oil mutant. The high oil mutant, p777, accumulated 8% more oil in seed than did wild type, but it showed no differences in seed size, plant growth or development. The high-oil phenotype is caused by the disruption of the GLABRA2 gene, a previously identified gene that encodes a homeobox protein required for normal trichome and root hair development. Knockout of GLABRA2 did not affect LEAFY COTYLEDON 1 and PICKLE expression in developing embryo. The result ...... |
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A chimeric AtMYB23 repressor induces hairy roots, elongation of leaves and stems,and inhibition of the deposition of mucilage on seed coats in Arabidopsis. Matsui K, Hiratsu K, Koyama T, Tanaka H, Ohme-Takagi M. Plant Cell Physiol. 2005 Jan;46(1):147-55. ...... addition to disruption of the development of trichomes. The short primary root and the elongation of leaves and stems appeared to be due to the reduced and enhanced lengthwise expansion, respectively, of epidermal cells. Expression of the GL2 gene, which is involved in the formation of root hairs and the accumulation of mucilage, was suppressed in both the roots and siliques of the transgenic plants. In contrast, the expression of genes related to cell elongation, such as ...... |
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The YORE-YORE gene regulates multiple aspects of epidermal cell differentiation in Arabidopsis. Kurata T, Kawabata-Awai C, Sakuradani E, Shimizu S, Okada K, Wada T. Plant J. 2003 Oct;36(1):55-66. ...... trichome structure of cer1 was normal, whereas that of the yre cer1 double mutant was heavily deformed, indicating that epicuticular wax is required for normal growth of trichomes. Double mutants of yre and trichome-morphology mutants, glabra2 (gl2) and transparent testa glabra1 (ttg1), showed that the phenotype of the trichome structure was additive, suggesting that the wax-requiring pathway is distinct from the trichome development pathway controlled by GL2 and TTG1. ...... |
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TRANSPARENT TESTA GLABRA2, a trichome and seed coat development gene of Arabidopsis, encodes a WRKY transcription factor. Johnson CS, Kolevski B, Smyth DR. Plant Cell. 2002 Jun;14(6):1359-75. ...... Mutants of a new gene, TRANSPARENT TESTA GLABRA2 (TTG2), show disruptions to trichome development and to tannin and mucilage production in the seed coat. The gene was tagged by the endogenous transposon Tag1 and shown to encode a WRKY transcription factor. It is the first member of this ...... |
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...... and in the atrichoblasts of developing roots. TTG2 acts downstream of the trichome initiation genes TTG1 and GLABROUS1, although trichome expression of TTG2 continues to occur if they are inactivated. Later, TTG2 shares functions with GLABRA2 in controlling trichome outgrowth. In the seed coat, TTG2 expression requires TTG1 function in the production of tannin. Finally, TTG2 also may be involved in specifying atrichoblasts in roots redundantly with other gene(s) but ...... |
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Overexpression of the AtmybL2 gene represses trichome development in Arabidopsis. Sawa S. DNA Res. 2002 Apr 30;9(2):31-4. ...... The amount of GL2 transcription was clearly reduced in the transgenic plants. Consistent with this, overexpression of AtmybL2 decreased beta-glucuronidase (GUS) activity in transgenic plants carrying a GUS-reporter gene regulated by the GL2 promoter. These findings, together with the results from our yeast two-hybrid analysis, suggest that GL3 gene function and overexpression of AtmybL2 act synergistically to inhibit trichome formation by negatively regulating GL2 expression. ...... |
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Entopically additive expression of GLABRA2 alters the frequency and spacing of trichome initiation. Ohashi Y, Oka A, Ruberti I, Morelli G, Aoyama T. Plant J. 2002 Feb;29(3):359-69. ...... GLABRA2 (GL2)/ATHB-10 encodes a homeodomain protein that belongs to the homeodomain-leucine zipper family. Mutant studies have revealed that this gene is involved in trichome, root-hair and seed-coat development. We used reverse genetics to ...... |
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...... of GL2 in trichome development. A transgene consisting of a GL2-coding fragment preceded by the cauliflower mosaic virus 35S promoter (35S::GL2) did not complement defects in the gl2-1 mutant. In the wild-type genetic background, 35S::GL2 caused gl2-mutant-like and scarcely viable phenotypes, suggesting that ectopic overexpression of GL2 interrupts endogenous GL2 function in trichome development and is toxic to plants. On the other hand, another GL2 transgene containing the ...... |
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...... gl2-1 mutation. Entopically additive expression of GL2 by introduction of pGL2::GL2 in the wild-type genetic background noticably increased the number of trichomes and induced production of adjacent trichomes. Consistent with this result, gl2-1/+ heterozygous leaves, whose GL2 expression was expected to decrease, had fewer trichomes than +/+ leaves. These results indicate that GL2 quantitatively regulates the frequency of trichome initiation and is involved in determining ...... |
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An upstream region of the Arabidopsis thaliana CDKA;1 (CDC2aAt) gene directs transcription during trichome development. Imajuku Y, Ohashi Y, Aoyama T, Goto K, Oka A. Plant Mol Biol. 2001 May;46(2):205-13. ...... developing trichomes, but not on proliferating tissues. On the other hand, another upstream fragment extending to the 5' non-coding transcribed region gave GUS activity to both proliferating tissues and developing trichomes. Against the gl2 mutant background, GUS activity directed by the 595 bp fragment was detected in single-stalk cells, but not in giant cells without obvious polar extension growth. These results revealed that the 595 bp fragment lacks cis element(s) ...... |
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Mosaic analysis of GL2 gene expression and cell layer autonomy during the specification of Arabidopsis leaf trichomes. Fyvie MJ, Murray JA, Kilby NJ. Genesis. 2000 Oct;28(2):68-74. ...... Homozygous glabra2 (gl2) mutant Arabidopsis thaliana Landsberg erecta plants with only a few rudimentary single spiked trichomes on the leaf margin were transformed with a genomic clone of GL2, resulting in partial restoration of the normal leaf trichome ...... |
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...... overlaying GUS sectors restricted to the L2 and/or L3 cell layers, retained the GL2 restored phenotype. These data support the view that the GL2 gene product acts in a region-autonomous manner within a single cell layer and indicate that GL2 gene expression in the L1 layer is sufficient for GL2-directed outgrowth of trichomes. Copyright 2000 Wiley-Liss, Inc. ...... |