| Title : Congenital End-Plate Acetylcholinesterase Deficiency Caused by a Nonsense Mutation and an A-->G Splice-Donor-Site Mutation at Position +3 of the Collagenlike-Tail-Subunit Gene (COLQ): How Does G at Position +3 Result in Aberrant Splicing? - Ohno_1999_Am.J.Hum.Genet_65_635 |
| Author(s) : Ohno K , Brengman JM , Felice KJ , Cornblath DR , Engel AG |
| Ref : American Journal of Human Genetics , 65 :635 , 1999 |
| Abstract : Congenital end-plate acetylcholinesterase (AChE) deficiency (CEAD), the cause of a disabling myasthenic syndrome, arises from defects in the COLQ gene, which encodes the AChE triple-helical collagenlike-tail subunit that anchors catalytic subunits of AChE to the synaptic basal lamina. Here we describe a patient with CEAD with a nonsense mutation (R315X) and a splice-donor-site mutation at position +3 of intron 16 (IVS16+3A-->G) of COLQ. Because both A and G are consensus nucleotides at the +3 position of splice-donor sites, we constructed a minigene that spans exons 15-17 and harbors IVS16+3A-->G for expression in COS cells. We found that the mutation causes skipping of exon 16. The mutant splice-donor site of intron 16 harbors five discordant nucleotides (at -3, -2, +3, +4, and +6) that do not base-pair with U1 small-nuclear RNA (snRNA), the molecule responsible for splice-donor-site recognition. Versions of the minigene harboring, at either +4 or +6, nucleotides complementary to U1 snRNA restore normal splicing. Analysis of 1,801 native splice-donor sites reveals that presence of a G nucleotide at +3 is associated with preferential usage, at positions +4 to +6, of nucleotides concordant to U1 snRNA. Analysis of 11 disease-associated IVS+3A-->G mutations indicates that, on average, two of three nucleotides at positions +4 to +6 fail to base-pair, and that the nucleotide at +4 never base-pairs, with U1 snRNA. We conclude that, with G at +3, normal splicing generally depends on the concordance that residues at +4 to +6 have with U1 snRNA, but other cis-acting elements may also be important in assuring the fidelity of splicing. |
| ESTHER : Ohno_1999_Am.J.Hum.Genet_65_635 |
| PubMedSearch : Ohno_1999_Am.J.Hum.Genet_65_635 |
| PubMedID: 10441569 |
Ohno K, Brengman JM, Felice KJ, Cornblath DR, Engel AG (1999)
Congenital End-Plate Acetylcholinesterase Deficiency Caused by a Nonsense Mutation and an A-->G Splice-Donor-Site Mutation at Position +3 of the Collagenlike-Tail-Subunit Gene (COLQ): How Does G at Position +3 Result in Aberrant Splicing?
American Journal of Human Genetics
65 :635
Ohno K, Brengman JM, Felice KJ, Cornblath DR, Engel AG (1999)
American Journal of Human Genetics
65 :635