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Updated: May 27, 2026

Measurement of Heme Synthesis Levels in Mammalian Cells
Published on: July 9, 2015
Intrinsic regulation of hemoglobin expression by variable subunit interface strengths
James M Manning1, Anthony M Popowicz, Julio C Padovan
1Department of Biology, Northeastern University, Boston, MA 02115, USA. j.manning@neu.edu
Abstract:
The expression of the six types of human Hb subunits over time is currently considered to be regulated mainly by transcription factors that bind to upstream control regions of the gene (the 'extrinsic' component of regulation). Here, we describe how subunit pairing and further assembly to tetramers in the liganded state is influenced by the affinity of subunits for one another (the 'intrinsic' component of regulation). The adult Hb dimers have the strongest subunit interfaces and the embryonic Hbs the weakest, with fetal Hbs being of intermediate strength, corresponding to the temporal order of their expression. These variable subunit binding strengths and the attenuating effects of acetylation contribute to the differences with which these Hb types form functional O(2) -binding tetramers consistent with gene switching.
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