Generating LacZ-reporter transgenic mice to identify α1 (XIX) Collagen (Col19a1) expression in Dermal Papilla Cells

Abstract

It is widely accepted the concept that tissue morphogenesis is mediated by reciprocal interactionsbetween epithelial and mesenchymal cells, whereas the molecular details of these interactions remainlargely elusive. The hair follicle (HF) is a mini-organ whose proper morphogenesis is governed by aseries of interactions between epidermal and dermal cells. Due to its relatively simple structure, the HFaffords an excellent model to decipher the molecular mechanisms of epithelial – mesenchymalinteractions. To explore the molecular mechanisms by which Dermal Papilla (DP) cells regulate hairfollicle formation, we performed a comparative transcriptome analysis and identified numerous genespreferentially expressed in the DP cells. Among these, a gene encoding type XIX Collagen (Col19a1)has become the focus of our attention because of its extensive evolutionary conservation. We generatedCol19a1LacZ reporter mice using CRISPR/Cas9 system to induce homologous recombination torecapitulate Col19a1 expression pattern. In mouse embryos, Col19a1LacZ expression is confined to theDP cells of hair follicles, ring sinus of whiskers, skeletal muscles and basal keratinocyte layer of skinepidermis of limbs and tail. Moreover, Col19LacZ started to be expressed at E14.5 in the dermalcondensates of hair germ stage to the DP cells of mature hair follicle but not in the placode stage.Ongoing generation of Col19a1 null mice will ultimately explore the functional role of Col19a1 duringHF morphogenesis. From this perspective, it is plausible to expect that future studies will provideadditional functional evidence for Col19a1 during development which might be a useful tool tounderstand the molecular mechanisms undergoing HF stem cell regulation