Gene fold-expression in burst-forming unit-erythroid (BFU-E) colonies under hypoxia and cellular normoxia after 14 days of cell culture. Comparison of sentrin-specific protease 1 (SENP1) (A), GATA-binding factor 1 (GATA1) (B), and erythropoietin (EPO) receptor (EPOR) (C) fold expression between chronic mountain sickness (CMS) and non-CMS cells in hypoxia and cellular normoxia. SENP1 expression in hypoxia in CMS and non-CMS samples, n = 10. SENP1 expression under normoxia in CMS and non-CMS samples, n = 9 and n = 10, respectively. GATA1 expression under hypoxia in CMS and non-CMS samples, n = 10 and n = 9, respectively. GATA1 expression under normoxia in CMS and non-CMS samples, n = 9 and n = 10, respectively. EPOR expression in hypoxia in CMS and non-CMS samples, n = 17 and n = 19, respectively. EPOR expression in normoxia in CMS and non-CMS samples, n = 12 and n = 15, respectively. Values expressed as means ± SE. *P < 0.05, **P < 0.01, ***P < 0.001.