uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
TFL2/LHP1 is involved in auxin biosynthesis through positive regulation of YUCCA genes
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Physiological Botany.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Physiological Botany.
Show others and affiliations
2011 (English)In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 65, no 6, 897-906 p.Article in journal (Refereed) Published
Abstract [en]

TERMINAL FLOWER2 (TFL2) is the plant homologue of metazoan HETEROCHROMATIN PROTEIN1 (HP1) protein family. It is known that, unlike most HP1 proteins, TFL2 does not primarily localize to heterochromatin; instead it functions in regulation of specific genes in euchromatic regions. We show that the tfl2 mutant has a lower rate of auxin biosynthesis, resulting in low levels of auxin. In line with this, tfl2 mutants have lower levels of expression of auxin response genes and retain an auxin response. The reduced rate of auxin biosynthesis in tfl2 is correlated to the down-regulation of specific genes in the tryptophan-dependent auxin biosynthesis pathway, a sub-set of the YUCCA genes. In vivo, TFL2 is targeted to a number of the YUCCA genes in an auxin-dependent fashion revealing a role of TFL2 in auxin regulation, probably as a component of protein complexes affecting transcriptional control.

Place, publisher, year, edition, pages
2011. Vol. 65, no 6, 897-906 p.
Keyword [en]
TERMINAL FLOWER2/LIKE HETEROCHROMATIN PROTEIN1, Aux/IAA, auxin response, auxin biosynthesis, YUCCA, epigenetic
National Category
Biological Sciences
URN: urn:nbn:se:uu:diva-150719DOI: 10.1111/j.1365-313X.2010.04470.xISI: 000288449700005PubMedID: 21251106OAI: oai:DiVA.org:uu-150719DiVA: diva2:408580
Available from: 2011-04-05 Created: 2011-04-05 Last updated: 2011-07-01Bibliographically approved
In thesis
1. Epigenetic Regulation of Light and Hormonal Signaling in Arabidopsis thaliana
Open this publication in new window or tab >>Epigenetic Regulation of Light and Hormonal Signaling in Arabidopsis thaliana
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Epigenetisk reglering av ljus och hormon signalering i Arabidopsis thaliana
Abstract [en]

Plants are stationary and need to adapt to the environment they live in. Integration of environmental cues, such as changes in light and temperature, can occur either directly or through the action of hormones. Hormone and light signaling leads to rapid changes in gene expression, and eventually changes in protein levels. In this thesis I have studied how the epigenetic regulator TERMINAL FLOWER2 (TFL2) is involved in light and hormonal signaling in the model organism Arabidopsis thaliana (thale cress). TFL2 is the only Arabidopsis homologue of HETEROCHROMATIN PROTEIN1 (HP1). HP1 proteins have been shown to be involved in repressing gene expression by maintaining the tight structure of heterochromatin or by forming a heterochromatin like structure in euchromatic regions. Unlike metazoan HP1 which can be localized both to eu- and heterochromatin, TFL2 is uniquely localized to euchromatin.

tfl2 mutants have reduced levels of free auxin and a reduced rate of auxin biosynthesis. TFL2 binds to and promotes spatial and temporal expression of the genes belonging to the YUCCA gene family, which are believed to regulate a rate limiting step in the auxin biosynthesis pathway. Further, TFL2 binds to a subset of Aux/IAA proteins to repress auxin regulated genes involved in ovule and carpel development. In a similar way, TFL2 is also involved in repressing two jasmonate responsive genes, VEGETATIVE STORAGE PROTEIN1 and 2. This TFL2 regulated repression might occur through the interaction with the jasmonate responsive protein JAZ6.

In light signaling TFL2 is involved in repressing both phytochrome A and B signaling as the response to red and far red light is enhanced in tfl2 mutants. The shade avoidance response and chloroplast biogenesis are also regulated by TFL2 as the hypocotyls of tfl2 are not able to elongate as wt in shade conditions and greening is delayed upon de-etiolation of tfl2 seedlings.

This work shows that TFL2 has a repressive function in auxin, jasmonate and light signaling and for the first time we show that TFL2 is directly involved in promoting gene expression.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2011. 52 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 837
TERMINAL FLOWER2, auxin, jasmonate, epigenetics, photomorphogenesis
National Category
Research subject
Biology with specialization in Physiological Botany
urn:nbn:se:uu:diva-151808 (URN)978-91-554-8099-8 (ISBN)
Public defence
2011-06-13, Lindhalssalen, EBC, Norbyvägen 18b, 75236, Uppsala, 13:15 (English)
Available from: 2011-05-23 Created: 2011-04-18 Last updated: 2011-07-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Rizzardi, Kristina
By organisation
Physiological Botany
In the same journal
The Plant Journal
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 228 hits
ReferencesLink to record
Permanent link

Direct link