Identification and expression pattern of zebrafish prox2 during embryonic development

Prox2, together with the previously isolated Prox1, is the vertebrate homolog of the Drosophila homeobox-containing gene prospero, the founder member of a family of transcription factors which have been shown to play critical roles in many developmental events. We have isolated a cDNA which encodes a putative protein that shares a high degree of homology with mammalian Prox1, Prox2, and zebrafish Prox1. Comparative genomic analysis revealed that this protein corresponds to the zebrafish Prox2 homolog being the gene syntenic with the chromosome region hosting mouse Prox2. Whole-mount in situ experiments demonstrated that prox2 is expressed, during zebrafish embryonic development, in defined structures of the central nervous system and the eye, as previously reported in mouse. Additionally, reverse transcriptase-polymerase chain reaction analysis disclosed prox2 expression in several adult organs. Finally, prox1 loss- and gain-of-function assays have been carried out to search for regulative effects on prox2 expression.