Single-base substitution at the last nucleotide of exon 6 (c.671G>A), resulting in the skipping of exon 6, and exons 6 and 7 in human succinyl-CoA:3-ketoacid CoA transferase (SCOT) gene.
Succinyl-CoA:3-ketoacid CoA transferase (SCOT, EC 2.8.3.5) is the key enzyme for ketone body utilization. Hereditary SCOT deficiency (MIM 245050) causes episodes of severe ketoacidosis. We identified a homozygous point mutation (c.671G>A) , which is a single-base substitution at the last nucleotide of exon 6, in a Turkish patient (GS12) with SCOT deficiency. This point mutation resulted in the skipping of exon 6, and exons 6 and 7 in human SCOT genes. To understand why the c.671G>A causes exons 6 and 7 skipping, nuclear RNA was separated from cytoplasmic RNA and both were analyzed by RT-PCR. In nuclear RNA, SCOT mRNA with exon 6 skipping was predominant and mRNA with exons 6 and 7 skipping was hardly detected, whereas the latter became one of major mRNA species in cytoplasmic RNA. This discrepancy was interpreted as follows: exon 6 skipping causes a frameshift and nonsense-mediated RNA decay in the cytosol, so mRNA with exon 6 skipping was unstable. On the other hand, SCOT mRNA with exons 6 and 7 is a minor transcript but it retains the reading-frame and is stable in cytosol. As a result, the latter mRNA is more abundant under steady-state conditions as compared to the former mRNA.
Yamada
Keitaro
K
Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1194, Japan.
Fukao
Toshiyuki
T
Zhang
Gaixiu
G
Sakurai
Satomi
S
Ruiter
Jos P N
JP
Wanders
Ronald J A
RJ
Kondo
Naomi
N
D000138:Acidosis / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002675:Child, Preschool; D015256:Coenzyme A-Transferases / Q000172:deficiency* / Q000235:genetics*; D004247:DNA / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D005091:Exons; D005260:Female; D006801:Humans; D017354:Point Mutation; D012326:RNA Splicing; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D017931:DNA Primers; D012333:RNA, Messenger; D004247:DNA; D015256:Coenzyme A-Transferases; C021460:3-ketoacid CoA-transferase