A mini-TGA protein modulates gene expression through heterogeneous association with transcription factors

Tomaž, Špela (author), Bajc, Gregor (author), Butala, Matej (author), Taler-Verčič, Ajda (author)

TGA (TGACG-binding) transcription factors, which bind their target DNA through a conserved basic region leucine zipper (bZIP) domain, are vital regulators of gene expression in salicylic acid (SA)-mediated plant immunity. Here, we investigated the role of StTGA2.1, a potato (Solanum tuberosum) TGA lacking the full bZIP, which we named a mini-TGA. Such truncated proteins have been widely assigned as loss-of-function mutants. We, however, confirmed that StTGA2.1 overexpression compensates for SA-deficiency, indicating a distinct mechanism of action compared with model plant species. To understand the underlying mechanisms, we showed that StTGA2.1 can physically interact with StTGA2.2 and StTGA2.3, while its interaction with DNA was not detected. We investigated the changes in transcriptional regulation due to StTGA2.1 overexpression, identifying direct and indirect target genes. Using in planta transactivation assays, we confirmed that StTGA2.1 interacts with StTGA2.3 to activate StPRX07, a member of class III peroxidases (StPRX), which are known to play role in immune response. Finally, via structural modeling and molecular dynamics simulations, we hypothesized that the compact molecular architecture of StTGA2.1 distorts DNA conformation upon heterodimer binding to enable transcriptional activation. This study demonstrates how protein truncation can lead to distinct functions and that such events should be studied carefully in other protein families.

• Language: English
• Keywords: mini-TGA proteins, plant immune response, TGA transcription factors, potato virus Y
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty; MF - Faculty of Medicine
• Publication status: Published
• Publication version: Version of Record
• Year: 2023
• Number of pages: Str. 1934–1952
• Numbering: Vol. 191, iss. 3
• PID: 20.500.12556/RUL-155110
• UDC: 578
• ISSN on article: 0032-0889
• DOI: 10.1093/plphys/kiac579
• COBISS.SI-ID: 135092739
• Publication date in RUL: 20.03.2024

Record is a part of a journal

• Title: Plant physiology
• Shortened title: Plant physiol.
• Publisher: Oxford University Press, American Society of Plant Biologists
• ISSN: 0032-0889
• COBISS.SI-ID: 5661703

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: proteini mini-TGA, rastlinski imunski odziv, transkripcijski faktorji TGA, virus krompirja Y