Developmental behaviour of zebrafish cellular nucleic acid binding protein (zCNBP).

LOMBARDO, V.; ARMAS, P.; WEINER A.; CALCATERRA, N. B.

Bariloche, Argentina.

Congreso; Bariloche Protein Symposium - Argentine Society for Biochemistry and Molecular Biology (SAIB) - XXXIX Annual Meeting. Biophysical Society of Argentina (SAB) - XXXII Annual Meeting.; 2003

Argentine Society for Biochemistry and Molecular Biology (SAIB) - Biophysical Society of Argentina (SAB).

CNBP is widespread throughout the animal kingdom. This protein shows an striking sequence conservation and general structural organisation which suggests it plays a fundamental biological role in different species throughout evolution. It was suggested to be involved in the developmental control of ribosomal proteins translation as well as in c-Myc expression regulation. We used the zebrafish Danio rerio as an animal model to study the CNBP behaviour during early development. We cloned and analysed zebrafish CNBP. zCNBP contains seven retroviral CCHC zinc finger motif, an RGG box and putative phosphorylation sites. Although its mRNA is detected in several adult tissues, we could observe a higher level of expression in ovary. We performed in vitro phosphorylation assays on GST-zCNBP fusion protein in presence of zebrafish embryo extracts from different developmental stages. We observed that zCNBP is phosphorylated in vitro in a differential way depending on the embryo developmental stage used. Band-shift assays were performed to analyse the ability of proteins present in embryo extracts to bind single-stranded probes of ribosomal protein 5´UTR and c-Myc 5´UTR. All the stages analysed were able to bind per se both probes, but their binding capacity varied through early development. A similar band-shift pattern was observed using GST-zCNBP instead embryo extracts. Therefore, the differential behaviour of CNBP during early development might have regulatory implications.