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Originally published Feb 14, 2017 and updated Jun 24, 2020.

Epigenetic modifications are an additional layer of control over gene expression that go beyond genomic sequence. Dysregulation of the epigenome (the sum of epigenetic modifications across the genome) has been implicated in disease states, and targeting the epigenome may make certain processes, like cellular reprogramming of iPSCs, more efficient. In general, epigenetic chromatin modifications are correlated with alterations in gene expression, but causality and mechanisms remain unclear. Today, targeted epigenetic modification at specific genomic loci is possible using CRISPR, and Addgene has a number of tools for this purpose.

By Susanna Bachle and Matt Takvorian

When COVID-19 researchers started working with us to help them share their reagents, we knew our role in fighting the pandemic could be even more impactful by reaching more scientists. Many members of the scientific community support open sharing. But, one critical part was missing when the COVID-19 plasmids first became available: distribution was limited to academic scientists.

Nanobodies from camelids have gotten a lot of press for being a promising approach for treatment or prophylaxis of COVID-19. Researchers identified nanobodies that bind to coronavirus spike proteins (Wrapp et al., 2020), which sit on the surface of coronaviruses and enable the virus to enter host cells. To do this, they injected the spike protein from two different coronaviruses into a llama over several days and isolated special camelid antibodies that bind to the spike proteins in cell culture, and inhibit these viruses. 

Not all plasmid preps are the same. Before purifying a plasmid from a bacterial culture, it is important to consider your experiment.  It will dictate the amount of DNA you need, and at which level of purity. Based on these premises we can classify a plasmid preparation in 3 different ways:

• Transformation grade DNA
• Cloning grade DNA
• Transfection grade DNA

Chemogentic and optogenetic technologies have pushed the boundaries in neuroscience by granting targeted control over neuronal activity. While they serve similar purposes, both techniques offer researchers different advantages and limitations. 

The four main factors in which chemogenetics and optogenetics differ are:

• Timing
• Targeted manipulation
• Controlling stimulation
• Invasiveness 

Choosing the best set of tools therefore depends on what you are looking to study.