A donor splice mutation (405 + 1 G → A) in cystic fibrosis associated with exon skipping in epithelial CFTR mRNA

We have studied the cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated chloride currents in pancreatic duct cells isolated from a transgenic cf/cf mouse created by targeted insertional mutagenesis. Adenosine 3',5'-cyclic monophosphate (cAMP)-activated CFTR chloride currents were detected in 78% (29/37) of wild-type cells, in 81% (35/43) of heterozygote cells, and in 61% (29/47) of homozygous cf/cf duct cells (P > 0.05, cf/cf vs. wild-type and heterozygote). The CFTR current density measured at membrane potentials of +/- 60 mV averaged 22-26 pA/pF in wild-type and heterozygote groups but only 13 pA/pF in cells derived from cf/cf animals (P < 0.05, cf/cf vs. wild-type and cf/cf vs. heterozygotes). In contrast, duct cells from animals of all three genotypic groups exhibited calcium-activated chloride currents that were of similar magnitude and up to 11-fold larger than the CFTR currents. We speculate that these transgenic insertional null mice do not develop the pancreatic pathology that occurs in cystic fibrosis patients because their duct cells contain 1) some wild-type CFTR generated by exon skipping and aberrant splicing and 2) a separate anion secretory pathway mediated by calcium-activated chloride channels.

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Mutational-screening in the factor VIII gene resulting in the identification of three novel mutations, one of which is a donor splice mutation

Human Mutation ◽

10.1002/(sici)1098-1004(1999)13:6<504::aid-humu14>3.0.co;2-9 ◽

1999 ◽

Vol 13 (6) ◽

pp. 504-504 ◽

Cited By ~ 3

Author(s):

Katharina M�ller-Morlang ◽

Kamiab Tavassoli ◽

Antonin Eigel ◽

Hartmut Pollmann ◽

J�rgen Horst

Keyword(s):

Factor Viii ◽

Splice Mutation ◽

Factor Viii Gene ◽

Novel Mutations ◽

Donor Splice ◽

Mutational Screening

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Exon skipping and circular RNA formation in transcripts of the human cytochrome P-450 2C18 gene in epidermis and of the rat androgen binding protein gene in testis.

Molecular and Cellular Biology ◽

10.1128/mcb.17.6.2985 ◽

1997 ◽

Vol 17 (6) ◽

pp. 2985-2993 ◽

Cited By ~ 104

Author(s):

P G Zaphiropoulos

Keyword(s):

Splice Site ◽

Exon Skipping ◽

Circular Rna ◽

Human Epidermis ◽

Donor Splice Site ◽

Acceptor Splice Site ◽

Donor Splice ◽

Exon 4 ◽

Androgen Binding ◽

Cytochrome P 450

The cytochrome P-450 2C18 gene was found by reverse transcription-PCR to represent the most abundantly expressed gene of the P-450 2C subfamily in human epidermis. However, in addition to the canonical mRNA of nine exons, transcripts that have skipped exon 4 or 5, exons 4, 5, and 6, or exons 4, 5, 6, and 7 were also identified in this tissue. Remarkably, circular RNA transcripts synthesized by the joining of the donor and acceptor splice sites of the same exon were detected in human epidermis for exons 4 and 5. Moreover, molecules composed of exons 4, 5, and 6 with the donor splice site of exon 6 joined to the acceptor splice site of exon 4 or composed of exons 4, 5, 6, and 7 with the donor splice site of exon 7 joined to the acceptor splice site of exon 4 were also found to be present in this tissue. In rat testis, a similar analysis allowed the detection of a circular RNA molecule composed of exons 6 and 7 of the androgen binding protein (ABP) gene, with the donor splice site of exon 7 joined to the acceptor splice site of exon 6, and of an ABP mRNA which had skipped exons 6 and 7. These results apparently substantiate the hypothesis that alternative pre-mRNA splicing has the potential to generate not only mRNAs that lack one or more exons but also circular RNA molecules that are composed of the exons that are skipped. However, additional 2C18 circular species containing various combinations of exons were also detected in human epidermis, and an exon 6-skipped ABP mRNA molecule was identified in rat testis. This observation is interpreted as indicative that at low frequency, numerous circular RNA formation and exon skipping events may occur, allowing the joining of a variety of different combinations of exons. Moreover, the relative stability of these molecules is apparently the key factor that determines the relative ease of their detection.

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Exon skipping caused by DNA recombination that introduces a defective donor splice site into the human glycophorin A gene.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)53487-6 ◽

1993 ◽

Vol 268 (7) ◽

pp. 4945-4952

Author(s):

C.H. Huang ◽

M.E. Reid ◽

O.O. Blumenfeld

Keyword(s):

Splice Site ◽

Dna Recombination ◽

Exon Skipping ◽

Donor Splice Site ◽

Glycophorin A ◽

Donor Splice ◽

Human Glycophorin

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The Effect of Synonymous Single-Nucleotide Polymorphisms on an Atypical Cystic Fibrosis Clinical Presentation

Life ◽

10.3390/life11010014 ◽

2020 ◽

Vol 11 (1) ◽

pp. 14

Author(s):

Giovana Bampi ◽

Anabela Ramalho ◽

Leonardo Santos ◽

Johannes Wagner ◽

Lieven Dupont ◽

...

Keyword(s):

Cystic Fibrosis ◽

Single Nucleotide Polymorphisms ◽

Protein Expression ◽

Protein Function ◽

Low Frequency ◽

Exon Skipping ◽

Cftr Gene ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Exon 11

Synonymous single nucleotide polymorphisms (sSNPs), which change a nucleotide, but not the encoded amino acid, are perceived as neutral to protein function and thus, classified as benign. We report a patient who was diagnosed with cystic fibrosis (CF) at an advanced age and presented very mild CF symptoms. The sequencing of the whole cystic fibrosis transmembrane conductance regulator (CFTR) gene locus revealed that the patient lacks known CF-causing mutations. We found a homozygous sSNP (c.1584G>A) at the end of exon 11 in the CFTR gene. Using sensitive molecular methods, we report that the c.1584G>A sSNP causes cognate exon skipping and retention of a sequence from the downstream intron, both of which, however, occur at a relatively low frequency. In addition, we found two other sSNPs (c.2562T>G (p.Thr854=) and c.4389G>A (p.Gln1463=)), for which the patient is also homozygous. These two sSNPs stabilize the CFTR protein expression, compensating, at least in part, for the c.1584G>A-triggered inefficient splicing. Our data highlight the importance of considering sSNPs when assessing the effect(s) of complex CFTR alleles. sSNPs may epistatically modulate mRNA and protein expression levels and consequently influence disease phenotype and progression.

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