Gain-of-function research

Lysine acetylproteome analysis reveals the lysine acetylation in developing fruit and a key acetylated protein involved in sucrose accumulation in Rosa roxburghii Tratt

Lysine acetylation is a common post-translational modification of proteins in plants. Rosa roxburghii Tratt. is an economically important fruit tree known for its high nutritional value. However, the characteristics of acetylome-related proteins during fruit development in this crop remain unknown. This study aimed to explore the global acetylproteome of R. roxburghii fruit to identify key lysine-acetylated proteins associated with its quality traits. A total of 4280 acetylated proteins were identified, among them, 981 proteins exhibited differential acetylation (DA) while 19 proteins showed increased acetylation level consistently on individual sites. Functional classification revealed that these DA proteins were primarily associated with central metabolic pathways, carbohydrate metabolism, terpenoids and polyketides metabolism, lipid metabolism, and amino acid metabolism, highlighting the importance of lysine acetylation in fruit quality formation. Notably, the most significant up-regulated acetylation occurred in sucrose synthase (SuS1), a key enzyme in sucrose biosynthesis. Enzyme assays, RNA-seq and proteome analysis indicated that SuS activity, which was independent of its transcriptome and proteome level, may be enhanced by up-acetylation, ultimately increasing sucrose accumulation. Thus, these findings offer a better understanding of the global acetylproteome of R. roxburghii fruit, while also uncover a novel mechanism of acetylated SuS-mediated in sucrose metabolism in plant. SIGNIFICANCE: Rosa roxburghii Tratt. is an important horticultural crop whose commercial value is closely linked to its fruit quality. Acetylation modification is a post-translational mechanism observed in plants, which regulates the physiological functions and metabolic fluxes involved in various biological processes. The regulatory mechanism of lysine acetylation in the fruit quality formation in perennial woody plants has not been fully elucidated, while most of the research has primarily focused on annual crops. Therefore, this study, for the first time, uses Rosaceae fruits as the research material to elucidate the regulatory role of lysine-acetylated proteins in fruit development, identify key metabolic processes influencing fruit quality formation, and provide valuable insights for cultivation strategies.

The Epistemic Value of Gain of Function Experiments

The phrase "gain of function" (GOF) has recently acquired a negative connotation in experimental biology by its association with risky science. Whereas much of the discussion on the relative merits of GOF-type experiments has focused on their risk-benefit equation, relatively little has been said about their epistemic value. In this article, we recount how GOF experiments were critical for establishing DNA as the genetic material, the identification of cellular receptors, and the role of oncogenes in cancer research. Today, many of the products of the biomedical revolution such as synthetic insulin, growth factors, and monoclonal antibodies are the result of GOF experiments where cells were given the new function of synthesizing medically important products. GOF experiments and complementary loss of function experiments are epistemically powerful tools for establishing causality in biology.