Knockout of Slc25a19 causes mitochondrial thiamine pyrophosphate depletion, embryonic lethality, CNS malformations, and anemia.
SLC25A19 mutations cause Amish lethal microcephaly (MCPHA), which markedly retards brain development and leads to alpha-ketoglutaric aciduria. Previous data suggested that SLC25A19, also called DNC, is a mitochondrial deoxyribonucleotide transporter. We generated a knockout mouse model of Slc25a19. These animals had 100% prenatal lethality by embryonic day 12. Affected embryos at embryonic day 10.5 have a neural-tube closure defect with ruffling of the neural fold ridges, a yolk sac erythropoietic failure, and elevated alpha-ketoglutarate in the amniotic fluid. We found that these animals have normal mitochondrial ribo- and deoxyribonucleoside triphosphate levels, suggesting that transport of these molecules is not the primary role of SLC25A19. We identified thiamine pyrophosphate (ThPP) transport as a candidate function of SLC25A19 through homology searching and confirmed it by using transport assays of the recombinant reconstituted protein. The mitochondria of Slc25a19(-/-) and MCPHA cells have undetectable and markedly reduced ThPP content, respectively. The reduction of ThPP levels causes dysfunction of the alpha-ketoglutarate dehydrogenase complex, which explains the high levels of this organic acid in MCPHA and suggests that mitochondrial ThPP transport is important for CNS development.
Lindhurst
Marjorie J
MJ
National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA. marjr@mail.nih.gov
Fiermonte
Giuseppe
G
Song
Shiwei
S
Struys
Eduard
E
De Leonardis
Francesco
F
Schwartzberg
Pamela L
PL
Chen
Amy
A
Castegna
Alessandra
A
Verhoeven
Nanda
N
Mathews
Christopher K
CK
Palmieri
Ferdinando
F
Biesecker
Leslie G
LG
D000740:Anemia / Q000151:congenital / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D027321:Anion Transport Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D002490:Central Nervous System / Q000002:abnormalities* / Q000378:metabolism*; D020964:Embryo Loss / Q000235:genetics / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000196:embryology / Q000378:metabolism; D007656:Ketoglutaric Acids / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D013835:Thiamine Pyrophosphate / Q000172:deficiency / Q000378:metabolism*
D027321:Anion Transport Proteins; D007656:Ketoglutaric Acids; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; C515239:Slc25a19 protein, mouse; D013835:Thiamine Pyrophosphate