Hybridization Parameters Revisited: Solutions Containing SDS

Ken Rose, John O. Mason, Richard Lathe
2002 BioTechniques  
Salt concentration governs nucleic acid hybridization according to the Schildkraut-Lifson equation. High concentrations of SDS are used in some common protocols, but the effects of SDS on hybridization stringency have not been reported. We investigated hybridization parameters in solutions containing SDS. With targets immobilized on nylon membranes and PCR-or transcription-generated probes, we report that the 50% dissociation temperature (T m *) in the absence of SDS was 15°C-17°C lower than
more » ... -17°C lower than the calculated T m . SDS had only modest effects on T m * [1% (w/v) equating to 8 mM NaCl]. RNA/DNA hybrids were approximately 11°C more stable than DNA/DNA hybrids. Incomplete homology (69%) significantly reduced the T m * for DNA/DNA hybrids (approximately 14°C; 0.45°C/% nonhomology) but far less so for RNA/DNA hybrids (approximately 2.3°C; approximately 0.07°C/% nonhomology); incomplete homology also markedly reduced the extent of hybridization. On these nylon filters, SDS had a major effect on nonspecific binding. Buffers lacking SDS, or with low salt concentration, gave high hybridization backgrounds; buffers containing SDS, or high-salt buffers, gave reproducibly low backgrounds. S h o r t Technical Re p o r ts ABSTRACT In transgenic animal models, the conservation of DNA sequences between the transgene and the host wild-type gene can complicate the evaluation of the expression
doi:10.2144/02331st01 pmid:12139257 fatcat:bzt3nk45t5gfrkc2j2d56pf4cu