Development of transgenic lines to study pituitary cell development and plasticity in medaka (Oryzias latipes)
Master thesis
Permanent lenke
https://hdl.handle.net/11250/3147922Utgivelsesdato
2024Metadata
Vis full innførselSamlinger
Sammendrag
The reproductive system is an important process highly regulated by hormones produced bythe pituitary gland, including the thyroid-stimulating hormone (Tsh) and the folliclestimulatinghormone (Fsh). The pituitary is a highly plastic organ and adapts hormoneproduction according to their demand. The mechanisms involved in this plasticity are poorlyknown, same as their regulation. To further study the development and plasticity of theseendocrine cell populations, this project developed two new transgenic lines in the model fishJapanese medaka (Oryzias latipes).First, a transgenic line named tg(tshbb:tdTomato) was produced, in which the gene encodingthe fluorescent protein tdTomato was under the control of the tshbb promoter. This lineallowed us to visualize the cells expressing the tshbb gene of which the function and locationremain mostly unknown to this day. A fluorescent cell population was observed between theeyes in developing transgenic medaka larvae. This could hopefully indicate that Tshbbexpression has successfully been visualized for the first time in this species, whereas furtherstudies are needed to characterize this endocrine cell population.Second, a transgenic line named tg(fshb:NTR-CFP/fshb:DsRed2) carried the gene encodingthe bacteria-derived protein nitroreductase and the fluorescence proteins CFP and DsRed2under the control of the fshb promoter. Nitroreductase expression is known to induce cellspecificapoptosis when treated with ronidazole. With these properties, the transgenic linecould be useful for investigating regeneration of removed tissue. Dissected brain- andpituitary tissue was kept in specific culture conditions which were shown to minimize tissuedegradation. In these conditions, high-concentration treatments of ronidazole demonstrated toablate Fsh cells. Regeneration of these cells was unfortunately not observed in this project, somore studies are needed to characterize their role in pituitary plasticity.Further development of the transgenic lines developed in this study will allow deeperinvestigation of these two endocrine cell populations of the pituitary gland. The unknownfunction of Tshbb may finally be discovered, and the regeneration of Fsh cells may beexplored deeper in the medaka.