Humans and old world monkeys have similar patterns of fetal globin expression

The expression of epsilon- and gamma -globin mRNA and protein has been dete rmined in three Old World monkey species (Macaca mulatta, Macaca nemestrina , and Cercopithecus aethiops). Using RT-PCR with primers for epsilon- and g amma -globin, both mRNAs were detected in early fetal stages, whereas at 12 8 days (85% of full term), only gamma was expressed. High-performance liqui d chromatography was used for separation and quantitation, and matrix-assis ted laser desorption/ionization mass spectrometry was used for identificati on of globin polypeptides. An alpha -globin polymorphism was observed in al l of the species examined. During fetal life, gamma -globin was the predomi nant expressed beta -type globin. The red blood cells of infants still cont ained substantial amounts of gamma -globin, which declined to negligible le vels in 14 weeks as beta -globin expression reached adult values. The ratio of gamma1- to gamma2-globins (equivalent to (G)gamma/(A)gamma in humans) w as approximately 2.5, similar to the (G)gamma/(4)gamma ratio observed in hu mans. Thus, gamma -globin gene expression in these Old World monkeys specie s has three features in common with human expression: expression of both du plicated y genes, the relative preponderance of gamma (1) over gamma (2) ex pression, and the delay of the switch from gamma- to beta -globin until the perinatal period. Thus, the catarrhines seem to share a common pattern of developmental switching in the beta -globin gene cluster, which is distinct from the timing of expression in either prosimians or the New World monkey s. Our results indicate that an Old World monkey, such as Rhesus, could ser ve as a model organism (resembling humans) for experimentally investigating globin gene expression patterns during the embryonic, fetal, and postnatal stages. (C) 2000 Wiley-Liss, Inc.