Alpha-, beta-, and gamma-mRNA levels in beta-thalassemia; transcriptional and translational differences in heterozygotes, homozygotes, and compound heterozygotes.
We have determined the relative levels of alpha-, beta-, and gamma- (G gamma- and A gamma-) mRNAs in the reticulocytes of patients with mild beta-thalassemia intermedia due to combinations of promoter mutations and a classical type of beta-thalassemia, as well as in their relatives. The expected differences in the alpha/beta-mRNA ratio confirmed the mild suppression of beta-mRNA synthesis, particularly in heterozygotes for the -101 (C-->T) promoter mutation and the large increase in the relative gamma-mRNA level in compound heterozygotes. A significant discrepancy between Hb F and gamma-mRNA levels, observed in previously published studies, was confirmed indicating a less efficient gamma-mRNA translation. When the two different gamma-mRNA (G gamma- and A gamma-) levels were determined it was observed that in beta-thalassemia heterozygotes the extra gamma-mRNA was primarily of the G gamma type suggesting a more efficient translation of the A gamma-mRNA. This difference disappeared in homozygotes and compound heterozygotes: both mRNAs (G gamma- and A gamma-) translate with an equal efficiency.
Smetanina
N S
NS
Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100, USA.
Gu
L H
LH
Simjanovska
L
L
Momirovska
A
A
Petkov
G H
GH
Adekile
A D
AD
Efremov
G D
GD
Huisman
T H
TH
D000328:Adult; D002648:Child; D005260:Female; D005914:Globins / Q000235:genetics*; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000097:blood*; D014158:Transcription, Genetic; D017086:beta-Thalassemia / Q000097:blood* / Q000235:genetics
D012333:RNA, Messenger; D005914:Globins