A 2ND, ELONGATED, ALPHA-2-GLOBIN MESSENGER-RNA IS PRESENT IN RETICULOCYTES FROM NORMAL PERSONS AND SUBJECTS WITH TERMINATING CODON OR POLY-A MUTATIONS

With an RT-PCR procedure we have identified a second, elongated, alpha 2-globin mRNA in reticulocytes of normal persons and of patients with alpha-thal, particularly those with mutations in the terminating codo n (TAA-->CAA; Hb Constant Spring; TAA-->TAT Hb Pakse) or in the poly A site (AATAAA-->AATAAG). This type of mRNA is elongated because a resu lt a cryptic poly A site 1048 bp past the terminating codon is used. E ven some 5% of the alpha 2-mRNA of normal persons is of the elongated type. Ouantitative data suggest high levels of this mRNA in heterozygo us and homozygous carriers of poly A mutations and low levels in patie nts with the terminating codon mutations. Hematological and Hb data su ggest that translation of these elongated mRNAs is minimal. No elongat ed alpha 1-mRNA has been observed. (C) 1995 Academic Press. Inc.