Photobiotin Modification of DNA

When photobiotin is irradiated in the presence of DNA the reaction process nonselectively couples a biotin label to every 100-200 base residues. The result is an oligonucleotide probe detectable by the use of (strept)avidin conjugates. The uses of photobiotin for DNA or RNA modification are summarized in Chapter 11, Section 4. 

The following protocol is based on the method of Forster et al. (1985). Some optimization may be necessary to obtain the best signal and activity for particular probes in hybridization assays. 

In subdued lighting conditions, dissolve photobiotin in water at a concentration of 1 pg/pl. Protect from light. 

Mix an equal volume of the photo biotin solution with the DNA probe solution. 

Place the solution in an ice bath and irradiate from above (about 10cm away) for 15 minutes using a sunlamp (such as Philips Ultrapnil MLU 300W, General Electric sunlamp RSM 275 W, or National Self-Ballasted BHRF 240-250 V 250 W W-P lamp). 

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