Cytoglobin Is a Respiratory Protein in Connective Tissue and Neurons, Which Is Up-regulated by Hypoxia

摘要: Cytoglobin is a recently discovered vertebrate globin distantly related to myoglobin, and its function unknown. Here we present the first detailed analysis of distribution expression cytoglobin. Northern Western blotting experiments show presence cytoglobin mRNA protein in broad range tissues. Quantitative PCR demonstrates an up-regulation levels rat heart liver under hypoxic conditions (22 44 h 9% oxygen). Immunofluorescence studies with three antibodies directed against different epitopes consistently connective tissue fibroblasts as well hepatic stellate cells. also chondroblasts osteoblasts shows decreased level upon differentiation chondrocytes osteocytes. located cytoplasm these cell types. Evidence exclusively nuclear localization cytoglobin, proposed, provided by transfection assays green fluorescent fusion constructs, which absence active import. The differential argues general respiratory this molecule, but rather indicates tissue-specific function. We hypothesize that may be involved collagen synthesis. was observed some neuronal subpopulations central peripheral nervous systems. Surprisingly, localized both nucleus neurons, indicating possible additional role