TY  - GEN
Y1  - 2008///
KW  - Mushroom Body 
KW  -  Platynereis dumerilii 
KW  -  telencephalon 
KW  -  evolution
TI  - The evolution of mushroom body and telencephalic cell types, studied by single cell expression profiling of Platynereis dumerilii larvae
ID  - heidok9582
N2  - One of the many ways to understand the evolution of elaborate organs such as the brain is to investigate the different cell types that constitute that organ. Cell types are defined by a unique combination of genes (molecular fingerprint) that specify the distinct morphological and physiological features that are characteristic of that cell type. In order to study the cell types in the brain of the developing annelid Platynereis dumerilii I have investigated the co-expression of several genes at cellular resolution. For this, I have developed a protocol, the so-called Whole Mount In Silico Expression Profiling (WMISEP), utilizing advanced image processing algorithms, whole mount in situ hybridization, immunostaining against acetylated tubulin and whole mount reflection confocal microscopy. The basic idea of the protocol is to acquire two color confocal image stacks, with one channel containing expression information for gene and the other channel containing the information of the axonal scaffold. The information in the axonal scaffold channel is then used to align several such images to a common reference average axonal scaffold image, and thus bringing the expression patterns into the same coordinate system. I conducted several experiments to illustrate the cellular resolution sensitivity and specificity of the protocol. WMISEP has been used to generate cell resolution expression of 72 genes. I also developed a cellular model of the 48 hour old Platynereis larval brain, which facilitated the generation of cellular gene expression profiles. Subsequently, I used several clustering techniques to cluster the larval brain cells and genes based on their expression profiles and spatial patterns respectively. As an example application of WMISEP, I investigated the evolution of mushroom bodies (MBs) and telencephalic cell types. Firstly, I investigated the anatomy, development and molecular fingerprint of Platynereis MB cells. Subsequently, I compared the anatomy and molecular fingerprint of Platynereis and insect?s MBs to test for deep homology. Furthermore, I investigated the expression of early telencephalon regionalization genes in Platynereis and showed that the vertebrate telencephalon patterning genes are expressed in a similar spatial orientation in the Platynereis larval brain, suggesting that the telencephalon patterning gene network already existed in the last common ancestor of all bilaterian animals. Finally, the Platynereis MB and vertebrate cortex/hippocampus develop from the same molecular regions with respect to the conserved molecular topography.
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/9582/
AV  - public
A1  - Tomer, Raju
ER  -