Monday, June 25, 2012

Friday, June 22, 2012

Have you ever thought about how TF find their binding sites?

Transcription factors (TFs) are proteins that regulate the expression of genes by binding sequence-specific sites on the chromosome. It has been proposed that to find these sites fast and accurately, TFs combine one-dimensional (1D) sliding on DNA with 3D diffusion in the cytoplasm. This facilitated diffusion mechanism has been demonstrated in vitro, but it has not been shown experimentally to be exploited in living cells. We have developed a single-molecule assay that allows us to investigate the sliding process in living bacteria. Here we show that the lac repressor slides 45 ± 10 base pairs on chromosomal DNA and that sliding can be obstructed by other DNA-bound proteins near the operator. Furthermore, the repressor frequently (>90%) slides over its natural lacO1 operator several times before binding. This suggests a trade-off between rapid search on nonspecific sequences and fast binding at the specific sequence.

http://www.sciencemag.org/content/336/6088/1595.full

Wednesday, June 13, 2012

Why day dreaming makes you smarter and more creative?

If you see me staring at a paper for too long, would you please nudge me out of my daydream? Being almost a matchless daydreamer myself, I really do want to belive this article. But I completely disagree. Daydreaming is definitely not working its magic on me no matter what scientists like to believe. I am getting dumber by the day-quote n quote maryem hussein.
 http://www.newyorker.com/online/blogs/frontal-cortex/2012/06/the-virtues-of-daydreaming.html