Biology subjects

Weissman, J. D.

Publications and source records attributed to Weissman, J. D..

3 recordsLinked to original sources

bioRxiv2025

Structure of Photosystem I-FCP from giant kelp uncovers drivers of antenna evolution across the red lineage

Brown algae and other red-algae-derived organisms such as diatoms are major contributors to global CO2 fixation via photosynthesis. To understand the photosynthetic function of brown algae, we obtained the structure of giant kelp Macrocystis pyrifera photosystem I (PSI) with a fucoxanthin-chlorophyll-protein (FCP) antenna and compared it to known structures from the red-algal lineage. We identified differences in M. pyriferas antenna composition, architecture and chlorophyll networks, as well as a pronounced variation in transmembrane hydrophobic thickness across the PSI-FCP supercomplex, with implications for photochemical function. Our work lays the foundation to understand kelps high photosynthetic productivity, reveals new drivers of antenna conservation and diversification, and sheds light on evolutionary relationships between organisms of the red lineage.

biochemistry↗

bioRxiv2025

Genome-Wide Discovery and Characterization of Terpene Synthases Contributing to Strawberry Aroma Metabolism

Strawberry (Fragaria X ananassa) is a globally cultivated fruit crop valued for its unique flavor and aroma. Major groups of volatile organic compounds that contribute to strawberry aroma include terpenes, fatty acid esters, furanones, and benzenoids. Understanding the biosynthetic genes and pathways underlying strawberry terpene metabolism provides resources for developing precision breeding strategies to improve strawberry aroma traits. Here we describe the genome-wide identification and functional analysis of the terpene synthase (TPS) family that governs terpene chemical diversity in strawberries. Mining of the allo-octoploid genome of the cultivar Royal Royce identified 75 TPS gene candidates. Biochemical characterization of 27 predicted mono-, sesqui- and di-TPS enzymes via in vitro activity assays and in vivo enzyme co-expression studies demonstrated a range of TPS activities that are relevant for the biosynthesis of two thirds of known strawberry terpenes as well as products not previously described in octoploid strawberry. Complementary metabolomic and transcriptomic studies across a diversity panel of strawberry accessions demonstrated substantial variation in the composition and abundance of more than 30 detected accession-specific and common terpene aromas, nine of which matching characterized TPS products. Analysis of a developmental time series of two accessions with contrasting aroma further revealed accession-specific alterations of terpene metabolism during fruit ripening. These results expand our understanding of strawberry aroma metabolism and characterized terpene aroma genes as a resource for the molecular breeding of desirable aroma traits. One-sentence summaryDiscovery and characterization of the terpene synthase family that controls the diversity of terpene aroma metabolism in accessions of strawberry. Significance StatementThe diverse class of terpenoids contributes to complex crop traits, including plant growth, stress resilience, pollination, nutrition, and aroma. The discovery of terpene-biosynthetic pathways in octoploid strawberry (Fragaria X ananassa) provides foundational knowledge of the diversity of terpenoid metabolism in this important specialty crop toward applications in improving aroma traits.

plant biology↗

bioRxiv2023

Transgenerational Epigenetic Inheritance of MHC Class I Gene Expression is Regulated by the CCAAT Promoter Element

Transgenerational epigenetic inheritance is defined as the transmission of traits or gene expression patterns across multiple generations that do not derive from DNA alterations. The effect of multiple stress factors or metabolic changes resulting in such inheritance have been documented in plants, worms and flies and mammals. The molecular basis for epigenetic inheritance has been linked to histone and DNA modifications and non-coding RNA. In this study, we show that mutation of a promoter element, the CCAAT box, disrupts stable expression of an MHC Class I transgene, resulting in variegated expression among progeny for at least 4 generations in multiple independently derived transgenic lines. Histone modifications and RNA polII binding correlate with expression, whereas DNA methylation and nucleosome occupancy do not. Mutation of the CCAAT box abrogates NF-Y binding and results in changes to CTCF binding and DNA looping patterns across the gene that correlate with expression status from one generation to the next. These studies identify the CCAAT promoter element as a regulator of stable transgenerational epigenetic inheritance. Considering that the CCAAT box is present in 30% of eukaryotic promoters, this study could provide important insights into how fidelity of gene expression patterns is maintained through multiple generations.

genetics↗