A β°-thalassemic β-globin RNA that is labile in bone marrow cells is relatively stable in HeLa cells

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Abstract
We have shown previously that a β-globin RNA-deficient β°-thalassemia is caused by a single base-pair deletion in codon 44 of the human β-globin gene1. The lack of β-globin RNA in erythroid cells of these affected individuals is due to extreme β-globin RNA instability (t1/2=30 min)2 We have further investigated the mechanism of this extreme lability by transiently expressing the β°-thalassemic allele in HeLa cells and assaying the stability of the β-globin RNA that is produced. Surprisingly, the β°-thalassemic RNA is much more stable in HeLa cells than in bone marrow cells. Apparently, developing erythroid cells have a mechanism for turning over this thalassemic RNA while cervical carcinoma cells do not. We also have assayed the stability of RNA derived from in vitro-mutagenized β-globin genes. In HeLa cells, β-globin RNAs harboring deletions in and around the translation initiation codon accumulate to steady-state levels that are similar to the level of normal β-globin RNA.