My work has focused on the function of RNA binding-proteins during early development in Xenopus. I first documented the expression pattern of members of the AU-rich element binding protein (ARE-BP) and of the polypyrimidin tract binding protein (PTB) families during development. Study of the expression patterns of five members of the ARE-BP family (AUF1, KSRP, HuR, TIA1 and TTP) has underlined the broad role and the redundancy of expression of four of these proteins. Conversely, the highly specific expression pattern of TTP in macrophages suggests a potential function for this ARE-BP in hematopoietic development. My study of the PTB family (PTBP1, PTBP2 and PTBP3), has showed that each paralog presents a unique pattern of expression emphasizing their diverse functions during development. From previous work in the lab we knew that morpholino mediated knockdown of both PTBP1 and EXOSC9, a component of the RNA exosome, generated similar defects in the dorsal fin morphology. To identify the molecular origin of these defects we realized the transcriptome analysis by high throughput sequencing (RNA-Seq) of both morphants embryos. I produced cDNA libraries of control and morphant embryos and the sequencing was performed at the Genoscope. Analysis of a known PTBP1 target showed that even modest modifications of alternative splicing could be detected in our data sets. In addition, because these defects are not found in the EXOSC9 morphants it validated its use as an additional screen to exclude splicing events not involved in the epidermal defects. Identification of RNA whose deregulation may be involved in the fin phenotype is currently under study for a set of candidate genes.
