Studies the Function and Mechanism of Dnaja3a/Dnaja3b and Interaction Molecules during the Embryonic Satges

The DnaJ families have been preserved throughout evolution and are important for protein translation, folding, unfolding, translocation, degradation, immune response, apoptosis and senescence physiologic roles. Recent research has revealed involvement of some of the DnaJ family members in various types of cancers. Tid1, the human homologue of the Drosophila Tid56 gene (has been classified as a tumor suppressor gene), encodes two alternative splicing isoforms, hTid1-L and hTid1-S. Tid1 belongs to DnaJA3 protein is the member of DnaJ family and act as co-chaperones interact with the Hsp70 chaperone by DnaJ domain. Both splice variants regulate the activity of Hsp70 proteins. However, they exhibit opposing biological activities in response to cytotoxic insults. The hTid1-L promotes apoptosis whereas hTid1-S suppresses it. Loss function of Tid1 resulted in embryonic lethality between E4.5 and E7.5, but blastocysts are viable. These data suggests that Tid1 may play an important role during early embryogenesis. In the preliminary data, we identified the zebrafish homologue of the hTid1 genes were DnaJA3a and DnaJA3b. By using RT-PCR analysis, the expression of DnaJA3a mRNA was ubiquitously during the developmental stages and adult tissues, whereas the expression of DnaJA3b mRNA was mainly at 72 and 96 hpf during the developmental stages and adult brain and muscle. In this proposal, our hypothesis will be tested to show that DnaJA3a and DnaJA3b are required for morphogenesis in zebrafish embryo and possible through the Wnt/-catenine signaling pathway. To test our hypothesis, we will specifically address the follow issues (Aim 1) To identify the DnaJA3a/DnaJA3b interaction molecules or co-factors during the development stages. (Aim 2) To investigate overexpression or knockdown of the DnaJA3a/DnaJA3b for studying somatogenesis and heart formation in zebrafish embryo by muscle (-actin) and heart (CMLC2) tissue specific promoter. (Aim 3) To characterize DnaJA3a/DnaJA3b and the interaction molecules function in vitro and in vivo. The findings derived from this proposal may provide essential insights into DnaJA3 interacting molecules and offer a rational target for molecular mechanism studies of embryogenesis.