Problems with expressing your gene? One of the potential stumbling blocks in heterologous gene expression is incompatible codon usage. Every amino acid can be encoded by more than one codon, and for every amino acid each organism has a favorite codon that it tends to use more often than the others. The availability of tRNA in the organism will reflect this codon usage bias. Read more »

Ever get too many hits from your Pubmed searches? Using field tags allows you to generate more specific searches than keywords alone, saving you from trawling through hundreds of irrelevant articles. Read more »

While browsing you tube I came across this really nice animation of DNA replication, transcription and translation complete with imaginative sound effects. I hope you enjoy it as much as I did. Read more »

Equipment for photographing DNA gels stained with ethidium bromide (or other fluorescent dyes), doesn’t have to cost thousands of dollars. These days, great pictures can be obtained with a standard digital camera and an orange filter. Here’s how. Read more »

What do you get when you cross a Pyrococcus DNA polymerase with a dsDNA binding domain? …a highly processive, high fidelity, lighting fast PCR work-horseThose Finnish wizards at Finnzymes have made that work-horse a reality with their Phusion polymerase. I had been meaning to try out this enzyme for quite a while, but never got around to it, then a problematic 11 kb amplification brought it back to mind. Read more »

I recently had a problem where I needed to cut out an expression cassette (a promoter coupled to a coding sequence) from one plasmid vector and paste it into another containing an expression cassette so I could get tandem expression of the two genes. The recipient vector had no suitable restriction sites for performing this operation so I was faced with the fairly lengthly task of introducing two new restriction sites on the recipient vector using quikchange, then amplifying the expression cassette and sub-cloning into the recipient. Not much fun. Read more »

Zymo research have launched a new plasmid miniprep kit that not only is has the coolest name of any kit on the market but is, the manufacturers claim, the fastest means of plasmid purification available. Read more »

A Nature Structural & Molecular Biology article published by Singer et al has provided a fascinating insight into the kinetics of RNA polymerase II during transcription. Read more »

The most comprehensive way to evaluate DNA concentration and purity is to use both UV spectrophotometeric measurements and agarose gel eletrophoresis. This quick reference guide gives an overview of the information that can be derived from both. Read more »

One of the most crucial steps in any cloning procedure is the preparation of the vector. Get it wrong and your chances of success will be drastically reduced. The overall aim for a good vector preparation is to obtain a fairly concentrated stock of undamaged, fully digested plasmid DNA that is free from contaminants. Missing any of these aims will affect the efficiency of the ligation and is the cause of many of the problems researchers have with cloning. Here are my top tips for vector preparation: Read more »