GIP1 may act as a coactivator that enhances transcriptional activity of LBD18 in Arabidopsis.
The LATERAL ORGAN BOUNDARIES DOMAIN/ASYMMETRIC LEAVES2-LIKE (LBD/ASL) gene family encodes a class of transcription factors harboring a conserved plant-specific lateral organ boundaries domain and plays a key role in lateral organ development of plants. Recent studies have revealed developmental functions of some LBD genes in Arabidopsis, rice, and maize. We have shown previously that LBD18/ASL20 promotes the emergence of lateral roots in Arabidopsis. LBD18 induces EXPANSIN14 (EXP14) expression by binding to a specific region of the EXP14 promoter. To further understand the molecular mechanism of LBD18 acting as a transcription factor, we isolated a protein interacting with LBD18 by screening an Arabidopsis cDNA library using the yeast two-hybrid system with LBD18 as bait. We found that GBF INTERACTING PROTEIN1 (GIP1) interacts with LBD18 in yeast and Arabidopsis protoplasts. Reverse-transcription-polymerase chain reaction analysis showed overlapping expression of GIP1 and LBD18 in various tissues of Arabidopsis such as roots, aerial parts, and rosette leaves. Transient gene expression assay results with Arabidopsis protoplasts indicated that GIP1 enhances transcriptional activity of LBD18 in the EXP14 promoter fused to the GUS reporter gene. These results show that GIP1 may act as a transcriptional coactivator of LBD18.
Department of Bioenergy Science and Technology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Republic of Korea.
Han Woo
HW
Lee
Department of Plant Biotechnology, Chonnam National University, Gwangju 500-757, Republic of Korea.
Jong Hwa
JH
Park
Department of Plant Biotechnology, Chonnam National University, Gwangju 500-757, Republic of Korea.
Moung Yeon
MY
Park
Department of Bioenergy Science and Technology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 500-757, Republic of Korea. Electronic address: jungmkim@jnu.ac.kr.
Jungmook
J
Kim
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D011523:Protoplasts / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C509716:GIP1 protein, Arabidopsis; C573049:LBD18 protein, Arabidopsis; D014157:Transcription Factors
Arabidopsis; Coactivator; G-box binding factor (GBF); GBF interacting protein 1 (GIP1); Lateral organ boundaries domain 18 (LBD18)