ABSTRACT
Precision pharmacology aims to manipulate specific cellular interactions within complex tissues. In this pursuit, we introduce DART.2 (drug acutely restricted by tethering), a second-generation cell-specific pharmacology technology. The core advance is optimized cellular specificity-up to 3,000-fold in 15 min-enabling the targeted delivery of even epileptogenic drugs without off-target effects. Additionally, we introduce brain-wide dosing methods as an alternative to local cannulation and tracer reagents for brain-wide dose quantification. We describe four pharmaceuticals-two that antagonize excitatory and inhibitory postsynaptic receptors, and two that allosterically potentiate these receptors. Their versatility is showcased across multiple mouse-brain regions, including cerebellum, striatum, visual cortex and retina. Finally, in the ventral tegmental area, we find that blocking inhibitory inputs to dopamine neurons accelerates locomotion, contrasting with previous optogenetic and pharmacological findings. Beyond enabling the bidirectional perturbation of chemical synapses, these reagents offer intersectional precision-between genetically defined postsynaptic cells and neurotransmitter-defined presynaptic partners.
ABSTRACT
Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) plays an essential role in the life cycle of the virus. Therefore, RT has been a primary target in the development of antiviral agents against HIV-1. Given the prevalence of resistant viruses, evaluation of the resistance profile of potential drug candidates is a key step in drug development. A simplified RT purification protocol would facilitate this process, as it provides an efficient method by which to purify RT variants for compound evaluation. Traditional purification protocols require the use of several columns to purify untagged RT. The entire procedure usually requires at least one week to complete. Herein, we report two novel methods that enable us to purify highly active RT in either one or two steps. First, a one-step purification protocol was developed by employing an affinity column that was prepared by conjugating an RNase H specific inhibitor (RNHI) with NHS-activated resin. Cell lysate containing RT was loaded onto the column followed by washing in the presence of 2mM Mn(2+). The RT retained in the column was eluted after soaking overnight in 10mM EDTA to retrieve the Mn(2+). In the other method, a vector was constructed that encodes RT fused to cleavable intein and AviTag (a biotin tag) sequences at the C-terminus. Cell lysate containing biotinylated RT was passed through a DE-52 column and then loaded onto an avidin column. Untagged RT was released from the column by reductive cleavage of the intein by DTT. These two methods significantly shorten the time required to purify untagged WT and mutant RTs.
