Evolutionary Dynamics of Floral Homeotic Transcription Factor Protein–Protein Interactions
Author
Bartlett, Madelaine; Thompson, Beth; Brabazon, Holly; Del Gizzi, Robert; Zhang, Thompson; Whipple, Clinton
Abstract
Protein–protein interactions (PPIs) have widely acknowledged roles in the regulation of development, but few studies have addressed the timing and mechanism of shifting PPIs over evolutionary history. The B-class MADS-box transcription factors, PISTILLATA (PI) and APETALA3 (AP3) are key regulators of floral development. PI-like (PIL) and AP3-like (AP3L) proteins from a number of plants, including Arabidopsis thaliana (Arabidopsis) and the grass Zea mays (maize), bind DNA as obligate heterodimers. However, a PIL protein from the grass relative Joinvillea can bind DNA as a homodimer. To ascertain whether Joinvillea PIL homodimerization is an anomaly or indicative of broader trends, we characterized PIL dimerization across the Poales and uncovered unexpected evolutionary lability. Both obligate B-class heterodimerization and PIL homodimerization have evolved multiple times in the order, by distinct molecular mechanisms. For example, obligate B-class heterodimerization in maize evolved very recently from PIL homodimerization. A single amino acid change, fixed during domestication, is sufficient to toggle one maize PIL protein between homodimerization and obligate heterodimerization. We detected a signature of positive selection acting on residues preferentially clustered in predicted sites of contact between MADS-box monomers and dimers, and in motifs that mediate MADS PPI specificity in Arabidopsis. Changing one positively selected residue can alter PIL dimerization activity. Furthermore, ectopic expression of a Joinvillea PIL homodimer in Arabidopsis can homeotically transform sepals into petals. Our results provide a window into the evolutionary remodeling of PPIs, and show that novel interactions have the potential to alter plant form in a context-dependent manner.
Key words: PISTILLATA, Poales, APETALA3, convergent molecular evolution, B-class MADS box genes, evolution of flower development.
Date
2016-02-22
Citation:
APA:
Bartlett, Madelaine, & Thompson, Beth, & Brabazon, Holly, & Del Gizzi, Robert, & Zhang, Thompson, & Whipple, Clinton. (February 2016).
Evolutionary Dynamics of Floral Homeotic Transcription Factor Protein–Protein Interactions.
,
(),
-
. Retrieved from
http://hdl.handle.net/10342/8528
MLA:
Bartlett, Madelaine, and Thompson, Beth, and Brabazon, Holly, and Del Gizzi, Robert, and Zhang, Thompson, and Whipple, Clinton.
"Evolutionary Dynamics of Floral Homeotic Transcription Factor Protein–Protein Interactions". .
. (),
February 2016.
March 18, 2024.
http://hdl.handle.net/10342/8528.
Chicago:
Bartlett, Madelaine and Thompson, Beth and Brabazon, Holly and Del Gizzi, Robert and Zhang, Thompson and Whipple, Clinton,
"Evolutionary Dynamics of Floral Homeotic Transcription Factor Protein–Protein Interactions," , no.
(February 2016),
http://hdl.handle.net/10342/8528 (accessed
March 18, 2024).
AMA:
Bartlett, Madelaine, Thompson, Beth, Brabazon, Holly, Del Gizzi, Robert, Zhang, Thompson, Whipple, Clinton.
Evolutionary Dynamics of Floral Homeotic Transcription Factor Protein–Protein Interactions. .
February 2016;
():
.
http://hdl.handle.net/10342/8528. Accessed
March 18, 2024.
Collections