High sensitivity analysis of gene expression in single embryonic somites using coupled reverse transcription-polymerase chain reaction.

We have developed a highly sensitive and reproducible method to detect the expression of specific genes in small tissue samples, such as a single embryonic somite. The procedure, which utilizes coupled reverse transcription-polymerase chain reaction (RT-PCR), was developed for evaluating the sequence of gene expression occurring in single somites during chick embryonic development. Comparisons of results obtained from using combinations of various RNA isolation methods and reverse transcription methods demonstrate that a protocol using a commercially available RNA isolation reagent (Tri Reagent) followed by optimized PCR, successfully detects low levels of mRNAs.