Severe Hb S‐β°‐thalassaemia with a T → C substitution in the donor splice site of the first intron of the β‐globin gene

Gonzalez‐Redondo, J. M.; Stoming, T. A.; Kutlar, Ferdane; Kutlar, Abdullah; McKie, Virgil; McKie, Kathleen T.; Huisman, T. H. J.

doi:10.1111/j.1365-2141.1989.tb06283.x

Cited by 46 publications

(10 citation statements)

References 26 publications

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“…Although down-regulation of the y-gene at the adult stage is initiated in the absence of a linked 13-globin gene (6) (19) or CACC box mutations (18) argues in favor of a cis-acting mechanism for impaired y-silencing. Since EKLF is present and active at both embryonic and adult stages (16,30), we presume that absence of 03-globin expression at the embryonic stage reflects more effective competition of the 6-and -y-globin genes for the LCR at early times by virtue of their proximity to the LCR and/or a regulatory milieu favoring their expression (8,13,25 (shaded circle) bound to the ,B-globin promoter (hatched box) mediates proteinprotein interactions with the LCR.…”

Section: Discussionmentioning

confidence: 99%

“…We previously proposed a possible role for EKLF during the y-globin to 13-globin switch (16) on the basis of the selective ,B-globin deficiency we observed in EKLF-1-mice and elevated fetal hemoglobin in human adults heterozygous for deletions of the ,B-globin promoter or for mutations in the CACC box of the 13-globin promoter (16)(17)(18)(19). By studying the expression profile of a human globin YAC transgene in EKLF-1-embryos, we demonstrate that EKLF is essential not only for expression of the human f3-globin gene, but also for proper silencing of the human y-globin gene.…”

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confidence: 99%

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Silencing of human fetal globin expression is impaired in the absence of the adult beta-globin gene activator protein EKLF.

Perkins

Gaensler

Orkin

1996

Proc. Natl. Acad. Sci. U.S.A.

139

133

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Globin genes are subject to tissue-specific and developmental stage-specific regulation. A switch from human fetal ('y)-to adult (,B)-globin expression occurs within erythroid precursor cells of the adult lineage. Previously we and others showed by targeted gene disruption that the zinc finger gene, erythroid Kruippel-like factor (EKLF), is required for expression of the f3-globin gene in mice, presumably through interaction with a high-affinity binding site in the proximal promoter. To examine the role of EKLF in the developmental regulation of the human y-globin gene we interbred EKLF heterozygotes (+/-) with mice harboring a human ,B-globin yeast artificial chromosome transgene. We find that in the absence of EKLF, while human f-globin expression is dramatically reduced, 'y-globin transcripts are elevated -5-fold. Impaired silencing of y-globin expression identifies EKLF as the first transcription factor participating quantitatively in the y-globin to f8-globin switch. Our findings are compatible with a competitive model of switching in which EKLF mediates an adult stage-specific interaction between the f3-globin gene promoter and the locus control region that excludes the y-globin gene.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Silencing of human fetal globin expression is impaired in the absence of the adult beta-globin gene activator protein EKLF.

Perkins

Gaensler

Orkin

1996

Proc. Natl. Acad. Sci. U.S.A.

139

133

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“…Sequences and positions of the amplifi cation primers and of the oligonucleotide probes used in the studies are given in table 1. The procedures for amplification and dot-blot analysis are given elsewhere [23][24][25][26], Table 2 lists the results of the hybridization experi ments for 252 ps chromosomes. All 134 |3S chromo somes, previously determined as having haplotype 19, were positive for the G -T substitution at position -657 5' to the AY-globin gene, while all but two were found to be positive for the C -G substitution at posi tion -369 5' to the Gy gene.…”

Section: Methodsmentioning

confidence: 99%

Certain Mutations Observed in the 5´ Sequences of the Gγ- and Aγ-Globin Genes of βs Chromosomes Are Specific for Chromosomes with Major Haplotypes

et al. 1991

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In this paper we describe the distribution of some specific sequence differences in the 5’ flanking regions of the ^Aγ- and ^Gγ-globin genes from 100 Black adult and 57 newborn SS patients from the southeastern United States, from 76 individuals with AS, S-β-thal, SC, AC, or A-β-thal, and from 31 normal individuals. Haplotypes for all adult individuals have been previously determined using various restriction endonucleases. The DNA samples were amplified, dot blotted, and hybridized with ³²P-labeled specific oligonucleotide probes. All 134 chromosomes with haplotype 19 were positive for the G → T substitution at position -657 (^Aγ), while 132 were also positive for the C→G mutation at -369 (^Gγ). The three specific changes for the chromosome with haplotype 20 were found on all 54 chromosomes with this haplotype. The C→T mutation at -158 5’ to ^Gγ was present on all 41 chromosomes with haplotype 3, and on two chromosomes with a related atypical haplotype. Normal and β-thal chromosomes with each of these substitutions had the same 5’ subhaplotype as β^s haplotypes 19 or 20, respectively. The close relationship between the occurrence of specific mutations and the haplotype of β^s chromosomes makes the determination of these haplotypes with specific oligonucleotide probes attractive with respect to time and expense.

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“…There are three possibilities ; translation in these aberrant transcripts is unsuccessful, the translation products from these transcripts are extremely unstable, or the translation products are not recognized by the antibody. In general, a mutation at the second nucleotide of the GT dinucleotide of the 5' splice donor site leads to aberrant splicing [7,[15][16][17]. Such a mutation often produces a transcript which skips the upstream exon or which utilizes a cryptic 5' donor site usually located in the following intron [4,7,171.…”

Section: Discussionmentioning

confidence: 99%

A Single Point Mutation in the Splice Donor Site of the Low‐Density‐Lipoprotein‐Receptor Gene Produces Intron Read‐Through, Exon‐Skipped and Cryptic‐Site‐Utilized Transcripts

Maruyama

Miyake

Tsuji

et al. 1995

European Journal of Biochemistry

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Familial hypercholesterolemia is a genetic disorder caused by niutations of the low-density-lipoprotein (LDL) receptor gene. We characterized the structures of LDL receptor mRNA transcripts in the fibroblasts of a homozygous patient carrying a single base substitution (T-C) at the 5' splice donor site of intron 12 of the LDL receptor gene. We identified three abei~ant transcripts as a consequence of intron-I 2 readthrough, exon-12 skipping and utilization of a cryptic splice donor site. Only a point mutation at the 5' splice donor site caused the production of three alternatively spliced products. None of these transcripts produced a functional LDL receptor protein in this patient.Keywords: low-density-lipoprotein receptor ; familial hypercholesterolemia ; splicing mutation ; read through. Hobbs et al. [4J described a Japanese homozygous FH patient who expressed two different-sized transcripts of the LDL receptor gene; the patient was proved to be a true homozygote carrying a point mutation at the splice donor site of intron 12 of the LDL receptor gene 131. The sizes of the transcripts of the LDL receptor gene in this mutation were about 5.3 kb and 8.4 kb [3, 41. Although the patient expressed an apparently normalsized 5.3 kb transcript, she did not produce the LDL receptor protein that cross-reacted with the monoclonal antibody against the LDL receptor protein [4].We have frequently found the identical mutation in Japanese FH patients. The patients, KIK, YS and MY 151, were true homozygotes for this mutation, whose phenotype belonged to the so-called 'null-allele' phenotype ; neither LDL binding nor LDL receptor protein synthesis was detected in their fibroblasts.According to Robberson et al. 161, the splice acceptor and donor sites of an exon are recognized and defined as a unit by the splicing machinery. Thus, a point mutation at a splice site leads to exon skipping and/or utilization of a cryptic splice site close to the site of mutation [6, 71.As the patient with the mutation at the splice donor site of intron 12 did not produce the functional LDL receptor, the nor- ~~ mal-sized transcript of 5.3 kb found in this patient 13, 41 is expected to result from skipping of exon 12 and/or utilization of a cryptic donor site in intron 1 2 close to the 5' splice site. The production of the 8.4-kb transcript, however, is hard to explain on the basis of the described rule [6,7]. Therefore, in the present study, we analyzed the structure of the transcripts in the fibroblasts of this patient. We identified three aberrantly spliced transcription products; one contained the entire intron 12, one skipped exon 12, and one utilized n cryptic splice site in intron 12. MATERIALS AND METHODSPatient. The proband, KIK, was a patient who visited our lipid clinic in the National Cardiovascular Center for precise examination of hypercholesterolemia. She was 4 years old and had severe hypercholesterolemia. As she was born from consanguineous marriage and her cultured skin fibroblasts showed a negligible amount of LDL receptor activity...

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Severe Hb S‐β°‐thalassaemia with a T → C substitution in the donor splice site of the first intron of the β‐globin gene

Cited by 46 publications

References 26 publications

Silencing of human fetal globin expression is impaired in the absence of the adult beta-globin gene activator protein EKLF.

Silencing of human fetal globin expression is impaired in the absence of the adult beta-globin gene activator protein EKLF.

Certain Mutations Observed in the 5´ Sequences of the <sup>G</sup>γ- and <sup>A</sup>γ-Globin Genes of β<sup>s</sup> Chromosomes Are Specific for Chromosomes with Major Haplotypes

A Single Point Mutation in the Splice Donor Site of the Low‐Density‐Lipoprotein‐Receptor Gene Produces Intron Read‐Through, Exon‐Skipped and Cryptic‐Site‐Utilized Transcripts

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