A rapid oxime linker-based library approach to identification of bivalent inhibitors of the Yersinia pestis protein-tyrosine phosphatase, YopH.

A bivalent tethered approach toward YopH inhibitor development is presented that joins aldehydes with mixtures of bis-aminooxy-containing linkers using oxime coupling. The methodology is characterized by its facility and ease of use and its ability to rapidly identify low micromolar affinity inhibitors. The generality of the approach may potentially make it amenable to the development of bivalent inhibitors directed against other phosphatases.

Genetic evidence does not support direct regulation of EDNRB by SOX10 in migratory neural crest and the melanocyte lineage.

Mutations in the transcription factor Sox10 or Endothelin Receptor B (Ednrb) result in Waardenburg Syndrome Type IV (WS-IV), which presents with deficiencies of neural crest derived melanocytes (hypopigmentation) and enteric ganglia (hypoganglionosis). As Sox10 and Ednrb are expressed in mouse migratory neural crest cells and melanoblasts, we investigated the possibility that SOX10 and EDNRB function through a hierarchical relationship during melanocyte development. However, our results support a distinct rather than hierarchical relationship. First, SOX10 expression continues in Ednrb null melanoblasts, demonstrating that SOX10 expression is not dependent on EDNRB function. Second, Ednrb expression persists in E10.5 Sox10null embryos, demonstrating that Ednrb is not dependent on SOX10 for expression in migratory neural crest cells. Third, over-expression of SOX10 in melanoblasts of mice that harbor null or hypomorphic Ednrb alleles does not rescue hypopigmentation, suggesting that SOX10 overexpression can neither complement a lack of EDNRB function nor increase Ednrb expression. Fourth, mice that are double heterozygous for loss-of-function mutations in Sox10 and Ednrb do not demonstrate synergistically increased hypopigmentation compared to mice that are single heterozygotes for either mutation alone, suggesting a lack of direct genetic interaction between these genes. Our results suggest that SOX10 does not directly activate Ednrb transcription in the melanocyte lineage. Given that SOX10 directly activates Ednrb in the enteric nervous system, our results suggest that SOX10 may differentially activate target genes based on the particular cellular context.

Gaining ground: assays for therapeutics against botulinum neurotoxin.

Owing in part to recently heightened concern over bioterrorism, interest in the mechanism of action of botulinum neurotoxin (BoNT) and development of effective therapeutic strategies has dramatically increased. The emergence of BoNT as an effective treatment for a variety of neurological disorders and its growing use in the cosmetic industry have also increased interest in developing effective countermeasures. Although recent attempts to create effective vaccines appear promising, the multitude of clinical and cosmetic uses of BoNT make mass vaccination against the toxin undesirable and impractical, leading to intensified efforts to develop effective therapeutics to combat large-scale intoxications. In this review, we examine the relevant and available in vitro cell-based assays and in vivo assays for drug discovery and development, especially with regard to the potential for medium- to high-throughput automation and its use in identifying physiologically relevant inhibitors.