In situ hybridization: an informative technique for pigment cell researchers

Many cellular events are regulated at the transcriptional level. Recent technical advances such as DNA microarray have made it possible to determine mRNA profiles of cultured cells or tissues. However, since it is still impossible to completely simulate the in vivo environment in culture conditions, mRNA profiles of cultured cells are not perfect representatives of original cells. Furthermore, for cells that exist at lower densities, mRNA profiling using tissue samples would be difficult. By using tissue in situ hybridization, mRNA levels of genes in tissues can be determined at cellular resolution. Although throughput of tissue in situ hybridization is not high enough for mRNA profiling, it may be sufficient to investigate temporal/spatial expression profiles of genes that are known to be important or found to be interesting in high-throughput transcriptome/proteome analyses. Recent technical advances have made it easier for everybody to perform tissue in situ hybridization using normal experimental instruments with sufficient sensitivity to detect most genes. Although this technique has been utilized mainly in developmental biology, it will be fully advantageous when combined with high-throughput comprehensive transcriptome/proteome analyses.