Hemoglobin as a novel protein developmentally regulated in neurons.

We have attempted to identify some novel genes which were found to be more highly expressed in the embryonic brain than in the adult brain. Consequently, one of these clones was identified as alpha-globin cDNA. Actually, alpha-globin mRNA was detected in the neurons. In addition, beta-globin mRNA was detected in the neurons as well. Both globin mRNAs were developmentally regulated in the same pattern. Subsequently, further examinations with antiserum to hemoglobin revealed the presence of hemoglobin in the neurons. Hemoglobin has, up to now, been known to be an important O2 transporter protein in erythrocytes. Moreover, hemoglobin is now considered to be also a very dangerous protein generating the toxic hydroxyl radical (.OH). We herein show the presence of hemoglobin and its regulation in the central nervous system, which may indicate the presence of a useful function regulating O2 homeostasis and a potential oxidative toxicity for neuronal cells.