Cloning And Tissue Distribution Of Neuroglobin & Gene Expression Changes In Cerebral Ischemic Model

It is well known that brain is the most sensitive organ to hypoxia. However for a long time, people didn't know whether there exists a specific gene for oxygen utilizing in brain. In 2000, Burmester reported a newly identified protein—neuroglobin (NGB), mainly expressed in nervous systems and retina. which is a monomer with high oxygen affinity. The oxygen-binding properties of neuroglobin are comparable to another oxygen-binding protein, myoglobin suggesting a similar function of neuroglobin in the brain. Studies revealed NGB binds oxygen reversibly and plays an important role in oxygen homeostasis of neural tissues. Other studies demonstrated that expression of NGB could be upregulated under hypoxic conditions and have neuro-protective function both in vitro and in vivo. These results showed that NGB might be a significant contributor to the pathophysiological course of hypoxic injury. However. relatively little is known about the changes of NGB expression in the brain after ischemic-hypoxic damage. The major content of our study included three parts as follows:1. We obtained the cDNA sequence of NGB in gerbil and studied its sub-cellular localization including tissue expression profile. The results showed that neuroglobin is a highly conserved gene in evolution. Sequence similarity analysis showed that the cDNA sequence of gerbil NGB is 99% to rat NGB(RnNGB), 96% to mouse NGB(MmNGB) and 88% to human NGB(HsNGB), respectively. Cellular localization revealed that NGB protein located in the cytoplasm of the neurons. NGB protein immunoreactive cells were widely distributed throughout normal gerbil brain. Cellular density distribution of NGB immuno-positive cells was cortex>hippocampus>thalamus and other regions.2. Using RT-PCR technique, we found the expression of NGB mRNA was significantly increased at 1 minute and reached a peak at 5 minutes in the acute...