• Title/Summary/Keyword: Homeodomain

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Purification of Caudal-Related Homeodomain Transcription Factor and Its Binding Characterization

  • Jeong, Mi-Suk;Hwang, Eun-Young;Kim, Hyun-Tae;Yoo, Mi-Ae;Jang, Se-Bok
    • Journal of Microbiology and Biotechnology
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    • v.19 no.12
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    • pp.1557-1564
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    • 2009
  • Human CDX2 is known as a caudal-related homeodomain transcription factor that is expressed in the intestinal epithelium and is important in differentiation and maintenance of the intestinal epithelial cells. The caudal-related homeobox proteins bind DNA according to a helix-turn-helix structure, thereby increasing the structural stability of DNA. A cancer-tumor suppressor role for Cdx2 has been shown by a decrease in the level of the expression of Cdx2 in colorectal cancer, but the mechanism of transcriptional regulation has not been examined at the molecular level. We developed a large-scale system for expression of the recombinant, novel CDX2, in Escherichia coli. A highly purified and soluble CDX2 protein was obtained in E. coli strain BL21(DE3)RIL and a hexahistidine fusion system using Ni-NTA affinity column, anion exchange, and gel filtration chromatographies. The identity and secondary structure of the purified CDX2 protein were confirmed by MALDI-TOF MS, Western blot, and a circular dichroism analyses. In addition, we studied the DNA-binding activity of recombinant CDX2 by ELISA experiment and isolated human CDX2-binding proteins derived from rat cells by an immobilized GST-fusion method. Three CDX2-binding proteins were found in the gastric tissue, and those proteins were identified to the homeobox protein Hox-D8, LIM homeobox protein 6, and SMC1L1 protein.

Intercellular Trafficking of Homeodomain Proteins

  • Kim, Seon-Won;Moon, Jun-Yeon;Jung, Jin-Hee;Chen, Xiongyan;Shi, Chunlin;Rim, Yeong-Gil;Kwon, Hey-Jin;Jackson, David;Datla, Raju;Joliot, Alain;Kim, Jae-Yean
    • The Plant Pathology Journal
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    • v.21 no.1
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    • pp.21-26
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    • 2005
  • Homeotic proteins have pivotal roles during the development of both plant and animals. Many homeotic proteins exert control over cell fate in cells where their genes are not expressed, i.e., in a non-cell autonomous manner. Cell-to-cell communication, which delivers critical information for position-dependent specification of cell fate, is an essential biological process in multicellular organisms. In plants, there are two pathways for intercellular communication that have been identified: the ligand/receptor-mediated apoplastic pathway and the plasmodesmata-mediated symplasmic pathway. Regulatory proteins and RNAs traffic symplasmically via plasmodesmata and play a critical role in intercellular communication. Thus, the non-cell autonomous function of homeotic proteins can be explained by the recent discovery of cell-to-cell trafficking of proteins or RNAs. This article specifically focuses on understanding the intercellular movement of homeodomain proteins, a family of homeotic proteins.

Functional characterization of Arabidopsis thaliana BLH 8, BEL1-Like Homeodomain 8 involved in environmental stresses (환경 스트레스에 관여하는 애기장대 BLH 8, BEL1-Like Homeodomain 8의 기능 분석)

  • Park, Hyeong-Cheol;Park, Ji-Young;Baek, Dong-Won;Yun, Dae-Jin
    • Journal of Plant Biotechnology
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    • v.38 no.2
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    • pp.162-168
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    • 2011
  • High salinity is a common stress condition that adversely affects plant growth and crop production. In response to various environmental stresses, plants activate a number of defense genes that function to increase the tolerance. To isolate Arabidopsis genes that are involved in abiotic stress responses, we carried out genetic screening using various mutant lines. Among them, the blh8 ($\b{B}$EL1-$\b{L}$ike $\b{H}$omeodomain $\underline{8}$) mutant specifically shows chlorotic phenotypes to ionic (specifically, $Na^+$ and $K^+$) stresses, but no differences in root growth. In addition, BLH8 is related to plant development and abiotic stress as predicted by a Graphical Gaussian Model (GGM) network program. It implies that BLH8 functions as a putative transcription factor related to abiotic stress responses. Collectively, our results show that gene network analysis is a useful tool for isolating genes involved in stress adaptation in plants.

Nuclear localization of Obox4 is dependent on its homeobox domain

  • Park, Geon Tae;Lee, Kyung-Ah
    • Clinical and Experimental Reproductive Medicine
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    • v.40 no.1
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    • pp.1-6
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    • 2013
  • Objective: Oocyte-specific homeobox 4 (Obox4) is preferentially expressed in oocytes and plays an important role in the completion of meiosis of oocytes. However, the Obox4 expression pattern has not been reported yet. In this study, we investigated the subcellular localization of Obox4 using a green fluorescent protein (GFP) fusion expression system. Methods: Three regions of Obox4 were divided and fused to the GFP expression vector. The partly deleted homeodomain (HD) regions of Obox4 were also fused to the GFP expression vector. The recombinant vectors were transfected into HEK-293T cells plated onto coated glass coverslips. The transfected cells were stained with 4',6-diamidino-2-phenylindol and photographed using a fluorescence microscope. Results: Mutants containing the HD region as well as full-length Obox4 were clearly localized to the nucleus. In contrast, the other mutants of either the N-terminal or C-terminal region without HD had impaired nuclear localization. We also found that the N-terminal and C-terminal of the Obox HD contributed to nuclear localization and the entire HD was necessary for nuclear localization of Obox4. Conclusion: Based on the results of the present study, we demonstrated that the intact HD region of Obox4 is responsible for the nuclear localization of Obox4 protein in cells.