Cloning, gene expression, and characterization of CP27, a novel gene in mouse embryogenesis

We report the full-length sequencing, tissue-specific expression, and immunolocalization of cp27, a novel gene in mouse embryogenesis. The cp27 gene was isolated and cloned from a mouse E11 lambdagt11 library using a peptide antibody that recognized a distinct expression pattern in mouse craniofacial development. The cp27 gene contains an open reading frame of 295 amino acids corresponding to a predicted molecular mass of 33kDa. On Western blots, a polyclonal antibody against CP27 detected a single epitope at 27kDa. The putative CP27 protein has an isoelectric point of 4.75 and features a distinct helix-loop-helix structure according to prediction algorithms. We have cloned the human cp27 gene and mapped it to a locus on the human chromosome 16 which is in proximity to several loci associated with inherited craniofacial diseases such as fanconi anemia type A. Northern blot analysis of RNA from multiple mouse tissues demonstrated high levels of expression in developing mouse teeth, heart, lung, and liver of a single transcript of approx. 1. 8kbp. In situ hybridization using a radioactive RNA probe resulted in distinct signals in the developing neuroepithelium, cerebellum, heart, lung, liver, teeth, salivary glands, and periosteum of developing bones. Immunohistochemical staining of developing mouse tissues detected epitopes specific for CP27 in the mesenchyme surrounding the primary brain vesicles, in basement membranes, in the periosteum, in salivary glands, and in the stellate reticulum of teeth. Thus, CP27 represents a unique gene product involved in mouse embryogenesis.