Functional characterization of striated muscle signaling protein Ankrd2 in aves

Principal Investigator: Dr Snezana Kojic 

            Muscle specific mechanosensors Ankrd2 and Ankrd1 have an important role in transcriptional regulation, myofibrillar assembly, cardiogenesis and myogenesis. Ankrd2 is involved in muscle cell signaling as a powerful regulator which participates in inter- and intracellular communication pathways. It interacts with transcription regulators, as well as with structural and signaling proteins. The role of Ankrd2 in the regulation of gene expression is strongly supported by its accumulation in the nucleus after muscle injury and in proliferating myoblasts. Apart from being characterized in humans and rodents, Ankrd2 and Ankrd1 were investigated in pig, sheep, chicken, bull and steer. The most intriguing recent finding is that Ankrd1, preferentially expressed in mammalian heart, is exclusively expressed in chicken skeletal muscle. This result directly imposes the question of function of avian Ankrd2, which is dominantly expressed in mammalian skeletal muscle. Thus, we speculate that Ankrd2, just like Ankrd1, changed its function during evolution. The aim of this project is to functionally characterize avian Ankrd2 using chicken model system as it bridges the evolutionary gap between mammals and other vertebrates. Mammalian and chicken genomes are very different in size, coding sequences and regulatory elements. Accordingly, the molecular mechanism underlying avian skeletal muscle development also differs. The characterization of chicken Ankrd2 include: in silico analysis of avian Ankrd2 gene and protein; determination of spatio-temporal expression patterns in adults and during myogenesis, testing if myostatin, the negative regulator of myogenesis, effects Ankrd2 expression, and finally functional analysis in myoblast proliferation, myogenic differentiation and apoptosis using chicken fetal myoblasts and myotubes in which Ankrd2 is silenced or overexpressed. We expect to obtain first data on avian Ankrd2 gene and protein, not determined so far. Our results will represent important contribution, since very limited information about MARP family members in non-mammalian animal models is available so far. As well, some information related to evolution of this small family of muscle specific regulatory proteins are expected. Moreover we will introduce novel animal model system of chicken fetal myoblasts, which could be useful for and facilitate characterization of others muscle and non-muscle specific biomarkers in our Laboratory.