Differential Expression of Murine Adult Hemoglobins in Early Ontogeny

摘要

A hemoglobin mutation is described that permits study of the expression of the two adult beta -globin genes throughout fetal and postnatal development. Mice with a mutation at the Hbb/sup s/, beta -globin locus, were used to study the relative levels of beta -s2major and beta -sminor globins specified by the mutant Hbb/sup s2/ haplotype during development. At 11.5 days of gestation beta -sminor comprised over 80% and beta -s2major under 20% of the adult beta-globin. The relative level of beta -sminor decreased through fetal development; at birth beta -sminor represented 33.7% of the beta -globin. The adult values of 71.0% beta -s2major and 29.0% beta -sminor globin are expressed in mice six days after birth. Because the two beta -globin genes are expressed in mice of the Hbb/sup 2s/ haplotype, both the beta -smajor and beta -sminor genes must be expressed in mice of the Hbb/sup s/ haplotype. Expression of the beta -sminor gene is elevated to 35.6% in Hbb/sup s2/ mice that have been bled repeatedly. Thus, the 5' beta -s2major and 3' beta -sminor genes of the Hbb/sup s2/ haplotype and, presumably the 5' beta -smajor and 3' beta -sminor genes of the Hbb/sup s/ haplotype, are regulated independently and are homologous to the 5' beta -dmajor and 3' beta -dminor genes of the Hbb/sup d/ haplotype. Mice of the Hbb/sup s2/ haplotype are better than mice of the Hbb/sup d/ haplotytpe for studying the mechanisms of hemoglobin switching because the Hbb/sup s2/ each of the three embryonic and two adult hemoglobins can be separated by electrophoresis. 17 refs., 3 figs. (ERA citation 10:040193)