Smetanina N S, Huisman T H
Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100, USA.
Am J Hematol. 1996 Aug;52(4):258-63. doi: 10.1002/(SICI)1096-8652(199608)52:4<258::AID-AJH4>3.0.CO;2-R.
Using a reverse transcription-polymerase chain reaction (RT-PCR) technique we determined the alpha 2/alpha 1, alpha/beta, and gamma/beta mRNA ratios in reticulocytes of 11 patients with seven different unstable beta chain variants, of 4 patients with two unstable alpha chain variants, in hemoglobin (Hb) D, Hb Porto Alegre, and Hb E heterozygotes, and in 8 patients with Hb X-beta 0-thalassemia (thal) (three D-beta 0-thal, one Porto Alegre = beta 0-thal, one Lulu Island-beta 0-thal, and three E-beta 0-thal). In addition, we determined the beta X/beta A mRNA ratios (X = unstable) in some Hb D heterozygotes and in 6 subjects with an unstable beta chain variant. Normal alpha/beta and beta X/beta A mRNA ratios were found in all heterozygotes tested, indicating that the respective mutations did not alter the stability of the mRNAs. The alpha/beta mRNA ratio in four Hb E heterozygotes averaged 4.21 (normal, 4.47), and that in 2 patients with Hb E-beta 0-thal and four alpha-globin genes (alpha alpha/alpha alpha) averaged a high 22.4. The gamma mRNA level in the Hb E heterozygotes was < 1% but varied greatly in patients with Hb E-beta 0-thal; the alpha/(gamma + beta) mRNA ratios in the 2 patients were 15.5 and 16.7, respectively. The large differences in alpha/beta and alpha/(gamma + beta) mRNA ratios in reticulocytes of subjects with AE and with E-beta 0-thal may be due to differences in the levels of normally-spliced beta E and abnormally-spliced beta E mRNAs. Only the latter is unstable and is preferentially produced in bone marrow and reticulocytes of Hb E-beta 0-thal patients, where it is rapidly degraded.
我们运用逆转录 - 聚合酶链反应（RT-PCR）技术，测定了11例患有7种不同不稳定β链变异体的患者、4例患有2种不稳定α链变异体的患者、血红蛋白（Hb）D杂合子、Hb阿雷格里港杂合子、Hb E杂合子以及8例Hb X - β0 - 地中海贫血（地贫）患者（3例D - β0 - 地贫、1例阿雷格里港 = β0 - 地贫、1例露露岛 - β0 - 地贫和3例E - β0 - 地贫）网织红细胞中的α2/α1、α/β和γ/β mRNA比值。此外，我们还测定了部分Hb D杂合子和6例患有不稳定β链变异体的受试者的βX/βA mRNA比值（X = 不稳定）。在所有检测的杂合子中均发现正常的α/β和βX/βA mRNA比值，这表明相应的突变并未改变mRNA的稳定性。4例Hb E杂合子的α/β mRNA比值平均为4.21（正常为4.47），2例患有Hb E - β0 - 地贫且有4个α珠蛋白基因（αα/αα）的患者该比值平均高达22.4。Hb E杂合子中的γ mRNA水平<1%，但在Hb E - β0 - 地贫患者中差异很大；这2例患者的α/（γ + β）mRNA比值分别为15.5和16.7。患有AE和E - β0 - 地贫的受试者网织红细胞中α/β和α/（γ + β）mRNA比值的巨大差异可能是由于正常剪接的βE和异常剪接的βE mRNA水平不同所致。只有后者不稳定，且优先在Hb E - β0 - 地贫患者的骨髓和网织红细胞中产生，并在那里迅速降解。
