Structural characterization of the beta-globin gene cluster in an individual expressing a very low level of G gamma globin chains.
We report the case of a normal individual displaying an extremely unbalanced G gamma/A gamma-globin ratio (G gamma-globin chains undetectable by urea/triton/ acrylamide gel electrophoresis and just reaching the threshold of detection by high performance liquid chromatography) associated with a very low level of G gamma-globin mRNA (at the most 5% of total gamma-mRNA after reverse transcriptase polymerase chain reaction determination). By DNA Southern blotting and sequencing, the very low level of G gamma-globin chains in this individual was found in association with subhaplotype [+ -----] (Hinc II 5' to epsilon, Xmn I 5' to G gamma, Hind III in G gamma and A gamma, Hinc II in and 3' to psi beta), with G gamma- and A gamma-globin gene sequences of the B type chromosome, and with a number of AT repeats in the locus control region hypersensitive site-2 site, similar to that reported to be associated with the Bantu beta S haplotype. These structural characteristics, described for the first time combined in the same individual, suggest that the G gamma/A gamma ratio in adults, is controlled by sequences distributed all along the beta-globin gene cluster.
Ville
T
T
Centre de Génétique Moléculaire et Cellulaire, CNRS UMR 106, Université Claude Bernard Lyon I, Villeurbanne, France.
Starck
J
J
Ouazana
R
R
Gonnet
C
C
Bouhass
R
R
Godet
J
J
D000293:Adolescent; D000462:Algeria / Q000208:ethnology; D001483:Base Sequence; D015139:Blotting, Southern; D002675:Child, Preschool; D002880:Chromosomes, Human, Pair 11 / Q000235:genetics*; D003241:Consanguinity; D004252:DNA Mutational Analysis; D005319:Fetal Hemoglobin / Q000032:analysis; D005796:Genes; D005914:Globins / Q000096:biosynthesis / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D012333:RNA, Messenger; D005914:Globins; D005319:Fetal Hemoglobin