Abstract:In patients with betao thalassaemia from Ferrara, beta globin mRNA sequences are either absent or structurally abnormal while in betao thalassaemia in Catania, beta globin mRNA sequences are present. In deltabeta thalassaemia there is a deletion of beta-like globin genes, while in betao Catania DNA, no beta globin gene deletion is detectable.
“…However, it is clear that it must be considerable, as cases of P-thalassaemia have been demonstrated due to defects at every possible level: gene deletion [2,3], transcription, post-transcriptional processing and inactive mRNA [3,4,27,28].…”
Complementary DNA enriched in sequences hybridizing to β‐globin mRNA was prepared with viral RNA‐dependent DNA polymerase and used as a probe for the presence of β‐globin mRNA in nuclear and cytoplasmic RNA from two Italian patients with β°‐thalassaemia. In both cases the β‐globin gene was present and cytoplasmic mRNAβ was absent; however, one case appeared to transcribe mRNAβ and to fail to process it, while the other appeared transcriptionally defective. Evidence is also presented that the low levels of hybridization usually found at high RNA/cDNAβ ratios in β°‐thalassaemia are due to δ‐globin mRNA; the melting profile of the hybrid formed has been determined and a low melting temperature relative to mRNAβ· cDNAβ demonstrated.
“…However, it is clear that it must be considerable, as cases of P-thalassaemia have been demonstrated due to defects at every possible level: gene deletion [2,3], transcription, post-transcriptional processing and inactive mRNA [3,4,27,28].…”
Complementary DNA enriched in sequences hybridizing to β‐globin mRNA was prepared with viral RNA‐dependent DNA polymerase and used as a probe for the presence of β‐globin mRNA in nuclear and cytoplasmic RNA from two Italian patients with β°‐thalassaemia. In both cases the β‐globin gene was present and cytoplasmic mRNAβ was absent; however, one case appeared to transcribe mRNAβ and to fail to process it, while the other appeared transcriptionally defective. Evidence is also presented that the low levels of hybridization usually found at high RNA/cDNAβ ratios in β°‐thalassaemia are due to δ‐globin mRNA; the melting profile of the hybrid formed has been determined and a low melting temperature relative to mRNAβ· cDNAβ demonstrated.
“…Previous studi~ (Ottolenghi et aL, 1976;Ramirez et al, 1976) have shown that at least a partial deletion of the 8-and ~-globin genes has occurred in (8 ~)°-tbalAg~PmiR since the plateau level of ~-globin cDNA hybridization is reduced in DNA of patients with this disease. The precise extent of this deletion could not be determined from these experiments.…”
“…Most often, there are decreased amounts of the specific globin messenger RNA which serves as a template for the synthesis of the affected globin chain (4)(5)(6). The messenger RNA deficit results from either globin gene deletions (7)(8)(9)(10) or transcriptional or post-transcriptional impairment of the expression of globin genes (11)(12)(13). Analysis of the hemoglobins synthesized in patients with thalassemia has not shown abnormalities in the primary structure of the globin chains (1)(2)(3).…”
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