Study of housekeeping gene expression in human keratinocytes using OLISA, a long-oligonucleotide microarray and q RT-PCR.

In recent years, applications of microarray platforms have been extended to different areas of research including cosmetic and pharmaceutical. Although microarray technology is still improving its sensitivity and flexibility, researchers often turn toward quantitative RT-PCR for data validation. Assessment of messenger RNA quantity by these methods is based on comparison with internal standard genes, mainly housekeeping genes, so called because their synthesis occurs normally at a constant level. However, numerous studies showed that expression of these genes could vary in given situations. Here, we report results on four housekeeping genes (GAPDH, beta-2 microglobulin, S40 and S26 ribosomal sub-units) with constant expression levels established on OLISA microarray using different keratinocyte cultures. Moreover, qRT-PCR validation demonstrates that S26 ribosomal is a good housekeeping gene on keratinocytes and skin studies. Our data indicate that S26 gene can be routinely used to standardize results to investigate differentially expressed genes in a healthy human skin.