Mass, Markus and Simo, Erika and Dragon, Stefanie (2003) Erythroid pyrimidine 5'-nucleotidase: cloning, developmental expression, and regulation by cAMP and in vivo hypoxia. Blood 102 (12), pp. 4198-4205.
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A characteristic process of terminal erythroid differentiation is the degradation of ribosomal RNA into mononucleotides. The pyrimidine mononucleotides can be dephosphorylated by pyrimidine 5'-nucleotidase (P5N-I). In humans, a lack of this enzyme causes hemolytic anemia with ribosomal structures and trinucleotides retained in the red blood cells (RBCs). Although the protein/nucleotide sequence of P5N-I is known in mammals, the onset and regulation of P5N-I during erythroid maturation is unknown. However, in circulating chicken embryonic RBCs, the enzyme is induced together with carbonic anhydrase (CAII) and 2,3-bisphosphoglycerate (2,3-BPG) by norepinephrine (NE) and adenosine, which are released by the embryo under hypoxic conditions. Here, we present the chicken P5N-I sequence and the gene expression of P5N-I during RBC maturation; the profile of gene expression follows the enzyme activity with a rise between days 13 and 16 of embryonic development. The p5n-I expression is induced (1) in definitive but not primitive RBCs by stimulation of beta-adrenergic/adenosine receptors, and (2) in definitive RBCs by hypoxic incubation of the chicken embryo. Since embryonic RBCs increase their hemoglobin-oxygen affinity by degradation of nucleotides such as uridine triphosphate (UTP) and cytidine triphosphate (CTP), the induction of p5n-I expression can be seen as an adaptive response to hypoxia.
|Institutions:||Biology, Preclinical Medicine > Institut für Physiologie > Prof. Dr. Rosemarie Baumann|
|Subjects:||600 Technology > 610 Medical sciences Medicine|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||09 Dec 2010 06:56|
|Last Modified:||09 Dec 2010 06:56|