Subcellular localization of tobacco MAPKs

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Subcellular localization of tobacco MAPKs Clegg, Alana

Abstract

Plants effect intracellular changes in response to a variety of external stimuli. Harpin, a bacterial elicitor from the bean halo-blight pathogen Pseudomonas syringae pv phaseolicola, and megaspermin, an oocyte elicitor secreted by Phythophtora megasperma H20, are both known to elicit a hypersensitive response (HR) iii tobacco. These elicitors also induce phosphorylation of a 48 kDa protein and a 46 kDa protein that have been identified as the Salicylic A c i d Induced Protein Kinase (SIPK), and Wound Induced Protein Kinase (WIPK) mitogen activated protein kinases (MAPKs) respectively. Previous work has shown that transient over-expression of SIPK causes lesion formation in tobacco leaves, suggesting a possible role for SIPK in regulating tobacco HR signaling. Extracellular Regulated Kinase (ERK), a mammalian homologue to SIPK and WIPK, has been shown to localize to different parts of the cell in response to a variety of stresses. The objective of this study was to determine the subcellular localization of the tobacco MAPKs, SIPK and WIPK, in response to challenge by harpin and megaspermin. Using both SIPK-GFP proteins and in situ immunolabeling of SIPK and WIPK, it was determined that the tobacco MAPKs were localized predominantly in the cytoplasm, with some nuclear localization. Upon challenge with harpin and/or megaspermin the phosphorylated forms of the probed MAPKs showed strong nuclear localization. In elicitor induced tobacco cultures, immunolabeling results showed strong nucleolar localization within the nucleus. These results are consistent with the model that activation of ERK-homologues by intracellular effectors leads to translocation of the activated MAPK from the cytoplasm to the nucleus, most likely to effect transcriptional regulation of stress-related genes.

Item Metadata

Title	Subcellular localization of tobacco MAPKs
Creator	Clegg, Alana
Publisher	University of British Columbia
Date Issued	2004
Description	Plants effect intracellular changes in response to a variety of external stimuli. Harpin, a bacterial elicitor from the bean halo-blight pathogen Pseudomonas syringae pv phaseolicola, and megaspermin, an oocyte elicitor secreted by Phythophtora megasperma H20, are both known to elicit a hypersensitive response (HR) iii tobacco. These elicitors also induce phosphorylation of a 48 kDa protein and a 46 kDa protein that have been identified as the Salicylic A c i d Induced Protein Kinase (SIPK), and Wound Induced Protein Kinase (WIPK) mitogen activated protein kinases (MAPKs) respectively. Previous work has shown that transient over-expression of SIPK causes lesion formation in tobacco leaves, suggesting a possible role for SIPK in regulating tobacco HR signaling. Extracellular Regulated Kinase (ERK), a mammalian homologue to SIPK and WIPK, has been shown to localize to different parts of the cell in response to a variety of stresses. The objective of this study was to determine the subcellular localization of the tobacco MAPKs, SIPK and WIPK, in response to challenge by harpin and megaspermin. Using both SIPK-GFP proteins and in situ immunolabeling of SIPK and WIPK, it was determined that the tobacco MAPKs were localized predominantly in the cytoplasm, with some nuclear localization. Upon challenge with harpin and/or megaspermin the phosphorylated forms of the probed MAPKs showed strong nuclear localization. In elicitor induced tobacco cultures, immunolabeling results showed strong nucleolar localization within the nucleus. These results are consistent with the model that activation of ERK-homologues by intracellular effectors leads to translocation of the activated MAPK from the cytoplasm to the nucleus, most likely to effect transcriptional regulation of stress-related genes.
Extent	11187835 bytes
Genre	Thesis/Dissertation
Type	Text
File Format	application/pdf
Language	eng
Date Available	2009-11-21
Provider	Vancouver : University of British Columbia Library
Rights	For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
DOI	10.14288/1.0091632
URI	http://hdl.handle.net/2429/15513
Degree	Master of Science - MSc
Program	Forestry
Affiliation	Forestry, Faculty of
Degree Grantor	University of British Columbia
Graduation Date	2004-11
Campus	UBCV
Scholarly Level	Graduate
Aggregated Source Repository	DSpace

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Rights

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.