PSTK is a novel gene associated with early lung injury in Paraquat Poisoning

AIMS

Paraquat Poisoning (PQ) can cause illness and death, and its main causes of mortality are acute respiratory failure and lung fibrosis. Early recognition of this condition and early treatment are vital. Thus, it is of importance to target the key genes controlling pathogenesis in the early stage of PQ.

MAIN METHODS

C57BL/6 mice were used for Paraquat intragastric administration as a model of PQ. Following a gene chip-based screening, the change of gene expression in the lung was further validated by bioinformatic analyses, co-expression network construction and real-time RT-PCR, Western blot and immunofluorescence assays.

KEY FINDINGS

2287 genes with differential expression were identified at the very early stage of PQ. From these, 76 genes that were linked to mitochondrion function were further pursued. Among these genes, PSTK was a phosphorylase kinase which serves a protective role in oxidative stress lung damage. PSTK was the central gene in a 30-gene network that is important for mitochondrial complex I assembly, mitochondrial apoptosis and mitochondrial fatty acid beta-oxidation, suggesting that they could conceivably be related to the pathogenesis of PQ induced lung damage. Lastly, we confirmed that PSTK was lowered in rodent lungs following PQ.

SIGNIFICANCE

PSTK emerges as a central gene in a network of mitochondrial function genes in PQ exposed mice. The functional role of PSTK in PQ induced lung injury warrants further examination.

Development of cultures capable of reducing perchlorate and nitrate in high salt solutions

An ion exchange process with biological perchlorate and nitrate destruction and reuse of spent regenerant brine has been proposed as an efficient and environmentally sound method to treat perchlorate-contaminated groundwater. A culture capable of reducing perchlorate and nitrate in spent ion exchange regenerant brine containing at least 30 g/L NaCl is needed for this to be feasible. A batch culture inoculated from activated sludge failed to acclimate to more than 15 g/L NaCl whether nitrate was present or not. A mixed culture inoculated from marine sediment was capable of simultaneously reducing 100mg/L perchlorate and denitrifying 500 mg/L nitrate within 5 h in a synthetic medium in the presence of 30 g/L NaCl. The growth conditions to maintain this culture in a healthy state required the addition of trace metals, Na2S, and phosphate. A second culture capable of removing 100 mg/L perchlorate from synthetic medium containing 60 g/L NaCl within 24 h was also developed.

A new regulatory domain on the TATA-binding protein

Recognition of the TATA box by the TATA-binding protein (TBP) is a highly regulated step in RNA polymerase II-dependent transcription. Several proteins have been proposed to regulate TBP activity, yet the TBP domains responsive to all these regulators have not been defined. Here we describe a new class of TBP mutants that increase transcription from core promoters in vivo. The majority of these mutations alter amino acids that cluster tightly on the TBP surface, defining a new TBP regulatory domain. The mutant TBP proteins are defective for binding the transcriptional regulator yNC2, are resistant to inhibition by yNC2 in vitro and exhibit allele-specific genetic interactions with yNC2. These results provide strong biochemical and genetic evidence that TBP is directly repressed in vivo, and define a new TBP domain important for transcriptional regulation.