Heider, B. | bioRxiv Science

bioRxiv2022

Horizontal transferred T-DNA and haplotype-based phylogenetic analysis uncovers the origin of sweetpotato

The hexaploid sweetpotato is one of the most important root crops worldwide. However, its genetic origins are controversial. In this study, we identified two progenitors of sweetpotato by horizontal gene transferred IbT-DNA and haplotype-based phylogenetic analysis. The diploid progenitor is the diploid form of I. aequatoriensis, contributed the B1 subgenome, IbT-DNA2 and lineage 2 type of chloroplast genome to sweetpotato. The tetraploid progenitor of sweetpotato is I. batatas 4x, donating the B2 subgenome, IbT-DNA1 and lineage 1 type of chloroplast genome. Sweetpotato derived from the reciprocal cross between the diploid and tetraploid progenitors and a subsequent whole genome duplication. We also detected biased gene exchanges between subgenomes. The B1 to B2 subgenome conversions were almost 3-fold higher than the B2 to B1 subgenome conversions. This study sheds lights on the evolution of sweetpotato and paves a way for the improvement of sweetpotato.

evolutionary biology↗

bioRxiv2022

4EBP1/2 support tumorigenicity and cell survival during energetic stress by translationally regulating fatty acid synthesis

Energetic stress compels cells to evolve adaptive mechanisms to maintain homeostasis. Here, we report that the negative regulators of mRNA translation initiation eukaryotic initiation factor 4E binding proteins 1/2 (4EBP1/2) are essential to promote the survival of mammalian cells and budding yeast under glucose starvation. Functionally, 4EBP1/2 inhibit fatty acid synthesis upon energetic stress via repression of Acetyl-CoA Carboxylase Alpha (ACACA) mRNA translation, sparing NADPH, to maintain intracellular redox balance. This has important relevance in cancers, as we uncovered that oncogene-transformed cells and glioma cells exploit the 4EBP1/2 regulation of ACACA expression and redox balance to combat energetic stress, thereby supporting transformation and tumorigenicity in vitro and in vivo. Clinically, high EIF4EBP1 (encoding 4EBP1) expression is associated with poor outcomes in several cancer types, including glioma. Our data reveal that 4EBP1/2 are conserved mediators of the survival response to energetic stress which are exploited by cancer cells for metabolic adaptation.

cell biology↗