#dcas9

[thatsnicebutimmarried]

How did getting your two cats to live together go? I want to get a cat but my bf already has a cat and I’m worried that in a few years when we want to move in together the cats will try to murder each other.

Introducing two new cats to each other is always a bit tricky and is going to depend on the cats. It’s usually best to introduce them slowly, bit by bit, usually having one in a separate room so the existing cat can get used to the new cat’s scent. With our cats, it went really easily. Tater was a little under a year old and Rhaegar was 2. I brought Tater over to my now-husband’s place and he was really chill because this was a new, and neutral environment for him. Cats are naturally social creatures, so when meeting in a neutral environment they are usually fine with each other. It’s when territory comes into play that things get iffy. Rhaegar wasn’t really territorial though, and was more confused. He just sort of followed Tater around from a distance. And then at some point Tater was like HI NEW FRIEND and Rhaegar was like WTF. But it didn’t take long for them to get used to each other and become buddies.

My mom’s cats have been a different story. Her oldest cat Maggie was NOT pleased when any of my mom’s kittens arrived. Even now, a few years later she still doesn’t really like any of the other cats, but she tolerates them. Sometimes she smacks Noodles just for existing. But Noodles is also an idiot who doesn’t realize that when Maggie is hissing and spitting at him from under the bed that means she doesn’t want to play and he needs to leave her alone or she’s gonna kick his ass. And his sister Minnie took a while to get used to the newest kitten, Leela. Maggie ignores Leela, tolerates Minnie, and hates Noodles. Noodles and Minnie are brother and sister so they are bonded. Noodles met Leela and decided she was his baby. Minnie was initially a little hissy towards Leela and even more so when her brother started doting on her, but has since grown to like her. Minnie and Leela kind of avoid Maggie because they know not to bother the cranky old lady. 

It’s unlikely your cats are gonna murder each other. It can take cats some time to get used to each other, but you’re more likely to see them avoiding each other and hissing at each other from across rooms for a while than actively fighting each other. There are a lot of articles and info all over the internet about how to introduce cats safely. And if you two move in together to a new place that is new to both of your cats, there won’t be existing territorialism to add to any potential unfriendliness. 

[pknoepfl]

CRISPR to make IPS cells: review of new Ding lab paper

CRISPR and IPS cells are two of my favorite things so when they come together as in a cool, new paper from Sheng Ding’s lab, I’m excited to read it and curious as to what the scoop is.

Since 2006-2007 when mouse and human reprogramming were first reported, many different methods have been explored to make induced pluripotent stem (IPS) cells. Along the way we’ve all learned quite a lot about how…

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[sickpapes]

HZhang, Y., Yin, C., Zhang, T., Li, F., Yang, W., Kaminski, R., et al. (2015). CRISPR/gRNA-directed synergistic activation mediator (SAM) induces specific, persistent and robust reactivation of the HIV-1 latent reservoirs. Scientific Reports epress. http://doi.org/10.1038/srep16277

When it comes to HIV/AIDS treatment, we live in a combination best-of-times/worst-of-times. In many parts of the world, HIV/AIDS remains a catastrophic issue. Yet for people with access to treatment, there now exist many highly effective ways to treat HIV and live a long, healthy life. There are many classes of HIV drugs, each of which functions by blocking a specific step of viral replication or maturation. When taken continuously, these treatments can reduce one’s viral load to undetectable levels, and can effectively make a person incapable of transmitting the virus. This is a truly amazing state of affairs, and we at Sick Papes stand in awe of the activists and scientists who fought for decades to bring us this day. (We also spit on the grave of the homophobic shit-head Presidential Administration who actively made the crisis worse.) (We also salute the brave people like rapper Mykki Blanco who are fighting the enduring stigma of HIV.)  

However! There is a major issue for all existing treatment regimens: they must be taken continually for one’s entire life, and even a short lapse can cause the virus to come roaring back. This is because there are reservoirs of cells in your body that house “silent” copies of the HIV virus that do not replicate at all, and are invisible to the current replication-blocking treatments; whenever a person stops taking their drugs, these silent reservoirs flare up. The forefront of research on HIV treatment is therefore to find ways to target and destroy these silent reservoirs of HIV positive cells in the body, the source of perpetual risk.

Today’s Sick Pape presents a proof-of-principal for a technique to kill these silent pockets of HIV+ cells in an otherwise healthy person. To do so, the authors take advantage of a bangin’ new technique for activating any gene-of-interest in the genome. This technique, which was invented independently by several labs, involves the perpetually press-shy Cas9 protein…but with a naughty twist. Whereas Cas9 typically cuts DNA (at a genomic location controlled by a 20-bp “guide RNA”), Cas9 can be made unable to cut DNA by mutating specific amino acids in the catalytic core of the enzyme. This catalytically dead Cas9 (”dCas9″) can be fused to transcriptional activator domain, and guided to a gene’s promoter, thus transcriptionally activating that gene [insert DJ airhorn sound]. What’s more, dCas9 can also be fused to a repressor domain, or any other functional domain. In other words, we can now turn on or off any gene in the genome at will: it’s lit. 

Wenfei Hu’s lab, located in downtown Philadelphia, took advantage of this technique to activate the HIV genome in the reservoir cells where the virus hides. Once HIV has been activated, these cells can be killed by the immune system and/or existing drugs. This is obviously dope - but do keep in mind that all of this work is done in cell culture, where it is trivial to deliver dCas9 and guide RNAs to the cells. To make this technique work in humans will take some doing, but man I think someone’s gonna figure out that pretty soon. After all, Cas9 was only discovered like an hour and a half ago, and already a whole army of TED-talking Equity bros are frothing at the mouth to get rich off drugs.

Many diseases are related to the mis-regulation of genes rather than mutations in their coding sequence. Thus, using dCas9 to regulate gene expression may turn out to be a very powerful tool for a variety of medical treatments, as well as for basic biology research. Just a few days ago a pape dropped using a dCas9-repressor to address muscular dystrophy, and dCas9 can even modulate the epigenome. As Cas9-related research gets increasingly privatized, we here at SickPapes sure do hope that their insatiable profit motives align with the public interest occasionally. Happy Holidays everyone!