Nvbeta-actin and NvGAPDH as normalization factors for gene expression analysis in limb regenerates and cultured blastema cells of the adult newt, Notophthalmus viridescens

The red-spotted newt has the ability to fully regenerate complex structures by creating a pool of dedifferentiated cells that arise in response to tissue injury. An understanding of the mechanisms involved in the regenerative ability of the newt is limited by a lack of characterized assays. This deficiency includes the cloning and validation of housekeeping genes for normalizing gene expression data. We describe the cloning, characterization and real-time quantitative PCR evaluation of the normalization potential of the newt homologues of cytoplasmic beta-actin and GAPDH during newt limb regeneration and within the blastemal B1H1 cell line. Nvbeta-actin demonstrates a heterogeneous expression during limb regeneration and may be associated with differentiation state. The level of Nvbeta-actin expression in B1H1 cultures under conditions of myogenesis and serum resupplementation varies with the treatment. NvGAPDH is ubiquitously expressed during limb regeneration and within B1H1 cultures and does not demonstrate overall variations in expression levels. Thus, NvGAPDH is a more appropriate normalization factor in gene expression analyses during limb regeneration and treatments of B1H1 cultures.