Large-scale forward genetic screening of zebrafish affecting thyroid development

Abstract

The thyroid follicular cells originate from the foregut endoderm and elucidating which genes and signaling pathways regulate their development is crucial for understanding developmental disorders as well as diseases in adulthood. We exploited unique advantages of the zebrafish model to carry an ENU-based forward mutagenesis screen aiming at identifying genes involved in the development and function of the thyroid follicular cells. ENU is an excellent chemical mutagen due to its high mutation efficiency and an indiscriminate selection of genes. A total of 1606 F2 families from 36 ENU treated founders was raised and embryos from F3 generation were collected at 5dpf to perform the whole embryo in situ hybridization with a cocktail probe of thyroid marker thyroglobulin(tg), pituitary marker thyroid stimulating hormone (tshba) to determine the mutagenic phenotype. Among the 1606 F2 families, 112 F2 mutant families with normal development stages except for thyroid dysfunction were identified and divided into three different groups according to their phenotypic characteristics. Further studies of the mutants are likely to shed more insights into the molecular basis of both the thyroid development and function in the zebrafish and vertebrate.