Hyunjin Pyo

Publications (2)10.86 Total impact

• Article: TERE; a novel cis-element responsible for a coordinated expression of genes related to programmed cell death and secondary wall formation during differentiation of tracheary elements.

  Hyunjin Pyo, Taku Demura, Hiroo Fukuda
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  ABSTRACT: The differentiation of water-conducting tracheary elements (TEs) is the result of the orchestrated construction of secondary wall structure, including lignification, and programmed cell death (PCD), including cellular autolysis. To understand the orchestrated regulation of differentiation of TEs, we investigated the regulatory mechanism of gene expression directing TE differentiation. Detailed loss-of-function and gain-of-function analyses of the ZCP4 (Zinniacysteine protease 4) promoter, which confers TE-specific expression, demonstrated that a novel 11-bp cis-element is necessary and sufficient for the immature TE-specific promoter activity. The 11-bp cis-element-like sequences were found in promoters of many Arabidopsis TE differentiation-related genes. A gain-of-function analysis with similar putative cis-elements from secondary wall formation or modification-related genes as well as PCD-related genes indicated that the cis-elements are also sufficient for TE-specific expression of genes. These results demonstrate that a common sequence, designated as the tracheary-element-regulating cis-element, confers TE-specific expression to both genes related to secondary wall formation or modification and PCD.
  The Plant Journal 10/2007; 51(6):955-65. · 6.16 Impact Factor
• Article: Spatial and temporal tracing of vessel differentiation in young Arabidopsis seedlings by the expression of an immature tracheary element-specific promoter.

  Hyunjin Pyo, Taku Demura, Hiroo Fukuda
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  ABSTRACT: The vascular system is a complex tissue composed of several vascular cell types. However, little is known about the differentiation process of each vascular cell in situ. In this study, we found that the expression of the Zinnia cysteine protease 4 (ZCP4) promoter is restricted to only immature tracheary elements (TEs) in situ. Therefore, we monitored the early TE differentiation process in young Arabidopsis seedlings using a fusion gene of the ZCP4 promoter and the beta-glucuronidase gene as a molecular marker. This approach revealed unique processes of vessel differentiation during early seedling development, in which discontinuous initiation of vessel element differentiation occurs at distinct regions, followed by the simultaneous differentiation of protoxylem vessels and bidirectional differentiation of metaxylem vessels to form a vessel in the plant body.
  Plant and Cell Physiology 11/2004; 45(10):1529-36. · 4.70 Impact Factor