P2.43 Monday, Jan. 5 Cartilage rescue in a zebrafish mutant following heterospecific expression of a lamprey SoxE gene LEE, E.M.*; MCCAULEY, D.W.; University of Oklahoma, Norman; University of Oklahoma, Norman email@example.com
Gene duplication is thought to be a driving force for generating novel evolutionary traits that have led to increased vertebrate diversity and complexity. The appearance of neural crest cells in the ancestral vertebrate has also been proposed to be a characteristic key to the evolution of vertebrates. Some vertebrate cartilages are derived from migrating chondrogenic neural crest cells. Expression of Sox9 in these cells regulates expression of Type II collagen, the major matrix protein in vertebrate cartilage. Sox9 is one of three SoxE transcription factors that arose as a result of gene duplication in the vertebrate lineage. Lampreys, the basal-most extant vertebrates also possess three duplicate SoxE genes, SoxE1, SoxE2, and SoxE3 whose expression patterns have previously been described by our group. Here we investigate the functional role of the lamprey (Petromyzon marinus) gene SoxE1 within the context of zebrafish (Danio rerio) cartilage development. The chondrogenic function of a SoxE gene might have been acquired in early vertebrates following duplication of the ancestral SoxE gene at the base of vertebrates. Here we show that the jefhi1134zebrafish mutant missing a functional Sox9a gene and lacking cartilage, shows partial rescue of cartilage development following heterotopic expression of lamprey SoxE1 mRNA. Our data suggest that neural crest and chondrogenic functions of SoxE genes may have arisen prior to SoxE duplication at the base of vertebrates, but that the chondrogenic role was likely acquired by different SoxE paralogs present in agnathan and gnathostome vertebrates.