Redundancy, Feedback, and Robustness in the Arabidopsis thaliana BZR/BEH Gene Family

• Published in: Frontiers in genetics Vol. 9; p. 523
• Main Authors: Lachowiec, Jennifer, Mason, G Alex, Schultz, Karla, Queitsch, Christine
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 13-11-2018
• Subjects: canalization; developmental robustness; Genetics; hypocotyl; plant; stochasticity; variance; variance; plant; BZR1; canalization; developmental robustness; stochasticity; hypocotyl; BES1
• ISSN: 1664-8021; 1664-8021
• DOI: 10.3389/fgene.2018.00523

Organismal development is remarkably robust, tolerating stochastic errors to produce consistent, so-called canalized adult phenotypes. The mechanistic underpinnings of developmental robustness are poorly understood, but recent studies implicate certain features of genetic networks such as functional redundancy, connectivity, and feedback. Here, we examine the
/
gene family, whose function contributes to embryonic stem development in the plant
, to test current assumptions on functional redundancy and trait robustness. Our analyses of
/
gene mutants and mutant combinations revealed that functional redundancy among these gene family members is not necessary for trait robustness. Connectivity is another commonly cited determinant of robustness; however, we found no correlation between connectivity among gene family members or their connectivity with other transcription factors and effects on developmental robustness. Instead, our data suggest that
, the earliest diverged family member, modulates developmental robustness. We present evidence indicating that regulatory cross-talk among gene family members is integrated by
to promote wild-type levels of developmental robustness. Further, the chaperone HSP90, a known determinant of developmental robustness, appears to act via BEH4 in maintaining robustness of embryonic stem length. In summary, we demonstrate that even among closely related transcription factors, trait robustness can arise through the activity of a single gene family member, challenging common assumptions about the molecular underpinnings of robustness.