Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)

A recently identified G to A mutation at the last nucleotide of exon 6 of the sterol 27-hydroxylase gene (CYP 27) in a patient with cerebrotendinous xanthomatosis (CTX) was shown here to cause alternative pre-mRNA splicing of the gene. Northern blot analysis of the patient's RNA revealed a broa...

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Main Authors: Wengen Chen, Shunichiro Kubota, Yousuke Seyama
Format: Article
Language:English
Published: Elsevier 1998-03-01
Series:Journal of Lipid Research
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0022227520332909
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author Wengen Chen
Shunichiro Kubota
Yousuke Seyama
author_facet Wengen Chen
Shunichiro Kubota
Yousuke Seyama
author_sort Wengen Chen
collection DOAJ
description A recently identified G to A mutation at the last nucleotide of exon 6 of the sterol 27-hydroxylase gene (CYP 27) in a patient with cerebrotendinous xanthomatosis (CTX) was shown here to cause alternative pre-mRNA splicing of the gene. Northern blot analysis of the patient's RNA revealed a broadened band in the human CYP 27 mRNA region compared to that of the normal sample, indicating that there may exist differently spliced mRNA species in the patient. RT-PCR produced three fragments in the patient, one was full-length size and the other two were of smaller sizes. Sequence analysis confirmed that the nucleotide of the full-length size was identical to that of the normal full-length cDNA, except for the G to A mutation at codon 362, which corresponds to the last nucleotide of exon 6. One of the smaller size species lacked exon 6 and the other was absent from the 3′ terminal 88 bp of exon 6 due to the use of an activated cryptic 5′ splice site in exon 6. The correctly spliced mRNA harbouring the G to A mutation was responsible for the deficiency of the sterol 27-hydroxylase activity, as confirmed by transfection experiment. Transfection of constructed minigenes, with or without the mutation, showed that correctly spliced mRNA was observed in the normal minigene while the mutant minigene was differently spliced. This is the first report of a G to A substitution at the last nucleotide of an exon resulting in both normal and abnormal pre-mRNA splicings, including exon skipping and activating of a coding region cryptic 5′ splice site. The results reveal a new molecular basis for the CTX and provide information on aberrant splicing of pre-mRNA in multi-exon genes. —Chen, W., S. Kubota, and Y. Seyama. Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX).
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spelling doaj.art-a43ee80506654fc19f1f6976822fc11e2022-12-21T20:44:15ZengElsevierJournal of Lipid Research0022-22751998-03-01393509517Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)Wengen Chen0Shunichiro Kubota1Yousuke Seyama2Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanDepartment of Physiological Chemistry and Metabolism, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanTo whom correspondence should be addressed.; Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanA recently identified G to A mutation at the last nucleotide of exon 6 of the sterol 27-hydroxylase gene (CYP 27) in a patient with cerebrotendinous xanthomatosis (CTX) was shown here to cause alternative pre-mRNA splicing of the gene. Northern blot analysis of the patient's RNA revealed a broadened band in the human CYP 27 mRNA region compared to that of the normal sample, indicating that there may exist differently spliced mRNA species in the patient. RT-PCR produced three fragments in the patient, one was full-length size and the other two were of smaller sizes. Sequence analysis confirmed that the nucleotide of the full-length size was identical to that of the normal full-length cDNA, except for the G to A mutation at codon 362, which corresponds to the last nucleotide of exon 6. One of the smaller size species lacked exon 6 and the other was absent from the 3′ terminal 88 bp of exon 6 due to the use of an activated cryptic 5′ splice site in exon 6. The correctly spliced mRNA harbouring the G to A mutation was responsible for the deficiency of the sterol 27-hydroxylase activity, as confirmed by transfection experiment. Transfection of constructed minigenes, with or without the mutation, showed that correctly spliced mRNA was observed in the normal minigene while the mutant minigene was differently spliced. This is the first report of a G to A substitution at the last nucleotide of an exon resulting in both normal and abnormal pre-mRNA splicings, including exon skipping and activating of a coding region cryptic 5′ splice site. The results reveal a new molecular basis for the CTX and provide information on aberrant splicing of pre-mRNA in multi-exon genes. —Chen, W., S. Kubota, and Y. Seyama. Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX).http://www.sciencedirect.com/science/article/pii/S0022227520332909cerebrotendinous xanthomatosissterol 27-hydroxylase genemutationalternative splicing
spellingShingle Wengen Chen
Shunichiro Kubota
Yousuke Seyama
Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)
Journal of Lipid Research
cerebrotendinous xanthomatosis
sterol 27-hydroxylase gene
mutation
alternative splicing
title Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)
title_full Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)
title_fullStr Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)
title_full_unstemmed Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)
title_short Alternative pre-mRNA splicing of the sterol 27-hydroxylase gene (CYP 27) caused by a G to A mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis (CTX)
title_sort alternative pre mrna splicing of the sterol 27 hydroxylase gene cyp 27 caused by a g to a mutation at the last nucleotide of exon 6 in a patient with cerebrotendinous xanthomatosis ctx
topic cerebrotendinous xanthomatosis
sterol 27-hydroxylase gene
mutation
alternative splicing
url http://www.sciencedirect.com/science/article/pii/S0022227520332909
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