Dynamic localization of germline specific RNA molecules in vivo

Antragstellerin: Kim Joana Westerich
Projektbeteiligte: Kim Joana Westerich
Fachbereich, Studienrichtung: Institut für Zellbiologie
Projekttitel: Dynamic localization of germline specific RNA molecules in vivo
Fördersumme: 5.000,00 Euro
Kontakt: Kim Joana Westerich


In the context of a collaborative research project, I visited the Marlow research laboratory at the Icahn School of Medicine at Mount Sinai in New York. Here, I studied the regulation of small molecules, termed RNAs, which drive specification of germ cells and therefore ensure that genetic information is passed on to the future generation.
In the first stages of development, the embryo is lacking an active genome and is therefore fully dependent on RNAs and other factors inherited by the mother. These maternal RNAs are degraded once genes within the embryo become active and the organism can produce its own RNAs. However, a certain cell population called germ cells is able to protect these maternal RNAs from the degradation process by using a special set of factors, including RNA binding proteins. Essentially, the preserved presence of maternal RNAs drives the establishment and maintenance of germ cell identity, thus ensuring fertility.
Using the zebrafish embryo as a model, the project aims to reveal the regulation of single RNA molecules in the cells of the intact organism. A relevant stage to observe how these molecules distribute within the cell is the so-called sphere stage. At this early time point, the embryo is around 4 hours old and the yet immature germ cells begin to specify and adopt their identity. This is followed by the first symmetric division of the cells. In this way, germ cells increase their numbers to about 30, before they reach the future gonad and develop into sperm or egg cells. Importantly, it has been suggested that these symmetric divisions are preceded by a dramatic change in the localization pattern of germline specific components such as vasa RNA. Therefore, to reveal the precise changes in germ cell specific RNA distribution at this critical developmental stage, I applied a high-resolution RNA labeling system called RNA Scope.
Matching with previous assumptions, our preliminary data suggests that the germ cell specific RNAs nanos and vasa densely accumulate in a specific area within the cell. Interestingly though, this accumulation is maintained as the cells enter the first symmetric division. Even several minutes after completion of the first symmetric germ cell division, nanos and vasa RNA remain localized in dense structures to the periphery of the cell. The described change of vasa RNA localization from an accumulated state to an even distribution within the cell is therefore likely to occur only at a later developmental time point, after specification of the germ cell has been initiated.
To address the temporal and spatial manner, in which the distribution of germ cell specific RNAs changes, a detailed analysis of the developmental time points that follow the sphere stage, along with an investigation of factors influencing this process, can be conducted in future studies. This will shed further light on the relation between RNA regulation and germ cell specification.
The project is planned as a sustainable long-term collaboration between the University of Münster (Institute of Cell Biology) and the Mount Sinai institution in New York. The goal is to initiate a new project in the biomedical relevant field of germline biology that brings together two novel and innovative techniques, which have been adapted and optimized in both research groups. The time in the Marlow laboratory has been an amazing experience. Learning the techniques and finding the right acquisitions and conditions was challenging and certainly an exciting task. Next to the interesting research field, I believe that this kind of exchange contributes a lot to experiencing science from a different perspective and connecting with young international students and researchers. I am confident that the project has a high future potential. By bringing together students from the WWU and the Mount Sinai Medicine School, it represents an ideal basis for a productive exchange among th e instit utions in science and research. Many thanks to WWU Förderprogramm Forschungsprojekte Studierender for this great opportunity!