341 reputation
26
bio website n/a
location Baltimore, MD
age 32
visits member for 2 years, 2 months
seen Jul 11 '13 at 0:43

I'm a biologist, trying to master R and Python to manage my data and automate common lab tasks.


May
11
comment Do gene expression levels necessarily correspond to levels of protein activation?
I think you'll find very few papers that demonstrate changes in mRNA levels by microarray, claim that an increase in the gene product's activity is responsible for the biological effect, and then stop. mRNA data is complicated, not useless. Almost anywhere that mRNA upregulation is reported, it will be followed by a measurement of the protein levels and other follow-on experiments to confirm the protein's involvement.
May
2
comment Why isn't the p16-INK4a gene involved in apoptosis expressed in heart or liver tissues?
That's a good question. The Nature paper referenced in the NYT article says it, but with no citation, and their tissue work backs it up. The GeneCard data does run counter to that, though. I'd add the caveat that the Nature paper is talking about mice, and mice handle senescence differently than humans do. For one thing, they don't turn off their telomerase.
May
2
comment Why isn't the p16-INK4a gene involved in apoptosis expressed in heart or liver tissues?
Yeah, that's an interesting question. I'd say main advantage of senescence in most tissues is that the cell gets to hang around and do its job. If it goes through apoptosis, it's going to need to be replaced. Senescence as a strategy, then, would keep overall proliferation rates lower in the tissue as a whole, which could have upsides, like limiting the potential for errors to creep in. Which one gets selected for in which tissue could definitely be influenced by the balance of those factors compared to reproduction time.