119— The Role of Post-Encoding Retrieval on Cognitive and Neural Representations of Spatial Environments

Spatial memory is an important ability for navigating around one’s surrounding environment. However, due to the challenges of developing experimental paradigms that utilize large scale, real-world environments, little research has analyzed, in detail, the development of cognitive maps over time. Past research in rodents has shown that hippocampal place-cells replay during periods of quiet wakefulness, suggesting that mental replay of recent spatial experiences is tied to the development of cognitive maps. In humans, we hypothesize that the development of cognitive maps could therefore be manipulated by having participants selectively recall recent navigational experiences. We analyzed the development of cognitive maps for novel, real-world spatial environments in two groups, a spatial sequencing group (SSG) and rote-retrieval group (RRG), over a period of 2 weeks using Google Street View software. After navigating through the environment, participants’ spatial memories were tested with either rote retrieval or spatial sequencing recognition tests. Our preliminary results suggest the RRG was more successful navigating previously learned routes than the SSG with more practice on the trained routes, whereas the SSG may have developed some ability to discover shortcuts by being encouraged to think more broadly about the routes they were learning, and not rely on memorization

Identifying Potential RNA Binding Domains in the Thumb Region of R2 Protein

Transposable elements are selfish mobile genetic elements able to replicate in the host genome and are classified as either DNA type elements or retrotransposons. In our study, we focus on R2 retrotransposable elements. Retrotransposable elements can reverse transcribe an RNA intermediate into DNA either before or during integration into the target genome. The R2 element exclusively inserts in the 28S rRNA genes via the mechanism of target primed reverse transcription (TPRT). For the TPRT mechanism to occur, the 5\u27 and 3\u27 ends of the RNA intermediate must bind to R2 protein before cleavage and insertion into a new genomic site can occur. Despite its importance in TPRT, RNA binding sequences of the R2 protein are not well understood. The objective of this study was to create single alanine replacements via site-directed mutagenesis in both the RYGLV and KPQQR sequences, which are highly conserved in the thumb domain of the R2 protein, and to isolate this mutated R2 protein for use in future assays. By examining the RNA binding properties of the R2 protein, we can further understand the TPRT mechanism and its overall role in retrotransposon success

L’année 2015 à travers le regard du comité de rédaction du Bulletin du cancer

International audienceThe 2015 Congresses in oncology took place worldwide. A selection by the editorial board of the Bulletin du Cancer of the best-rated abstracts and published papers was presented including diverse oncology topics by organ location specificity. These highlights are a summary of the large amount of data presented and discussed during the major meetings dedicated in oncolog