Project description:We used RNA-Seq to ask whether the transcripts for the proposed BCKDH subunits are upregulated in wild-type plants subjected to prolonged darkness. These experiments were performed using rosette leaves from 5-week-old, short-day-grown (8h light/16h dark) Col-0 wild-type plants moved to constant darkness for 6h, 24h, 48h and 72h, and grown in short day for 72h as control. The transcripts of eight BCAA catabolism genes were increased nine- to 400-fold within the first 6h of prolonged darkness, and remained high until the last time point. These results are consistent with the hypothesis that BCAA catabolic enzymes - including BCKDH subunits E1A1, E1B1, E1B2 and E2 - have one or more physiological roles in the dark. Rosette leaf mRNA profiles of 5-week old Col wild type (WT, CS60000) and BCAA catabolic mutants ivd1-2 and hml1-2 were generated byRNA sequencing, in duplicate, using Illumina HiSeq2500.
Project description:We used RNA-Seq to ask whether the transcripts for the proposed BCKDH subunits are upregulated in wild-type plants subjected to prolonged darkness. These experiments were performed using rosette leaves from 5-week-old, short-day-grown (8h light/16h dark) Col-0 wild-type plants moved to constant darkness for 6h, 24h, 48h and 72h, and grown in short day for 72h as control. The transcripts of eight BCAA catabolism genes were increased nine- to 400-fold within the first 6h of prolonged darkness, and remained high until the last time point. These results are consistent with the hypothesis that BCAA catabolic enzymes - including BCKDH subunits E1A1, E1B1, E1B2 and E2 - have one or more physiological roles in the dark.
Project description:Branched‐chain amino acid (BCAA) metabolism is a central hub for energy production and regulation of numerous physiological processes. Controversially, both increased and decreased levels of BCAAs are associated with longevity. Using genetics and multi‐omics analyses in Caenorhabditis elegans, we identified adaptive regulation of the ubiquitin‐proteasome system (UPS) in response to defective BCAA catabolic reactions after the initial transamination step. Worms with impaired BCAA metabolism show a slower turnover of a GFP‐based proteasome substrate, which is suppressed by loss‐of‐function of the first BCAA catabolic enzyme, the branched‐chain aminotransferase BCAT‐1. The exogenous supply of BCAA‐derived carboxylic acids, which are known to accumulate in the body fluid of patients with BCAA metabolic disorders, is sufficient to regulate the UPS. The link between BCAA intermediates and UPS function presented here sheds light on the unexplained role of BCAAs in the aging process and opens future possibilities for therapeutic interventions.
Project description:Altered cellular metabolism in kidney proximal tubule (PT) cells plays a critical role in the development and progression of acute kidney injury (AKI). The transcription factor Krüppel-like factor 6 (KLF6) is rapidly and robustly induced in the PT after AKI, suggesting an early-inducible injury response gene. PT-specific Klf6 knockdown (Klf6PTKO) are protected from AKI and resulting fibrosis in mice. Combined RNA-sequencing and ChIP-sequencing demonstrated preserved expression of genes encoding branched chain amino acid (BCAA) catabolic enzymes in Klf6PTKO mice, with several of the genes also having KLF6 binding sites close to their transcription start sites. Conversely, inducible KLF6 overexpression suppressed expression of BCAA genes and exacerbated kidney injury and fibrosis in mice. Injured kidney cells could not respond to the BCAA catabolic activator BT2, and injured cells overexpressing KLF6 were less able to utilize BCAA. Thus, targeting KLF6-mediated suppression of BCAA catabolism may serve as key therapeutic target in AKI and kidney fibrosis.