Activation of multiple cryptic donor splice sites by the common congenital afibrinogenemia mutation, FGA IVS4 + 1 G-->T.

Abstract

Our recent studies on the molecular basis of the autosomal recessive disorder congenital afibrinogenemia showed that the most common mutation is a donor splice mutation in FGA intron 4, IVS4 + 1 G-->T, accounting for approximately half of disease alleles. The effect of this mutation on messenger RNA (mRNA) splicing, however, remained unproven. COS-7 cells transfected with a normal plasmid construct produced 100% mRNA molecules with correct splicing, whereas cells transfected with a mutant construct produced multiple aberrant mRNAs, due to utilization of cryptic donor splice sites situated in exon 4 and intron 4. One particular site situated 4 base pairs (bp) downstream of the normal site was used in 85% of transcripts causing afibrinogenemia by a 4-bp insertion-frameshift, leading to premature alpha-chain truncation. Our results confirm the utility of transfecting COS-7 cells to study mRNA splice-site mutations and demonstrate that the common FGA IVS4 variant is a null mutation leading to afibrinogenemia.

• Authors: C Attanasio, P de Moerloose, S E Antonarakis, M A Morris, M Neerman-Arbez
• Journal: Blood (Blood) Vol. 97 Issue 6 Pg. 1879-81 (Mar 15 2001) ISSN: 0006-4971 [Print] United States
• PMID: 11238133 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• RNA Splice Sites
• Fibrinogen

Topics

• Afibrinogenemia (congenital, etiology, genetics)
• Animals
• Base Sequence
• COS Cells
• Exons (genetics)
• Fibrinogen (genetics)
• Humans
• Molecular Sequence Data
• Point Mutation
• RNA Splice Sites (genetics)
• Transfection