Embryonic hemoglobin
chemical compound
Embryonic hemoglobin is a tetramer produced in the blood islands in the embryonic yolk sac during the mesoblastic stage (from 3rd week of pregnancy until 3 months). The protein is commonly referred to as hemoglobin ε. Hemoglobin is made up of four globin chains along with a heme group that contains an iron atom responsible for binding oxygen, with each molecule including two α-type globin and two β-type globin. The genes that produce the alpha chains are located together in a cluster on chromosome 16 and the genes for beta chains form from a separate cluster on chromosome 11.
In humans, the earliest blood islands containing primitive erythroid cells appear in the yolk sac at roughly 17 days of development. These first erythrocytes are large, nucleated cells that produce globin chains and begin circulating in the embryo around day 22, coinciding with the onset of cardiac activity.
Although adult hemoglobin is well known to science, embryonic hemoglobin is considered little-known due to its difficult nature being acquired and given ethical contradictions. In recent years, transgenic mice have been able to overcome those difficulties and allow research of embryonic hemoglobins in their native states. Comparing embryonic globin and hemoglobins in humans and mice allow scientists to study their evolutional purposes by looking at when each form is expressed, which globin subunits they contain, and which erythroid or non-erythroid cell types they are associated with.
Functions
The physiologic properties of embryonic hemoglobin include high oxygen affinity.
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This entry incorporates text from “Embryonic hemoglobin” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.