A mutation in a mitochondrial transmembrane protein is responsible for the pleiotropic hematological and skeletal phenotype of flexed-tail (f/f) mice

Genes Dev. 2001 Mar 15;15(6):652-7. doi: 10.1101/gad.873001.


We have studied the flexed-tail (f) mouse to gain insight into mammalian mitochondrial iron metabolism. Flexed-tail animals have axial skeletal abnormalities and a transient embryonic and neonatal anemia characterized by pathologic intramitochondrial iron deposits in erythrocytes. Mitochondrial iron accumulation is the hallmark of sideroblastic anemias, which typically result from defects in heme biosynthesis or other pathways that lead to abnormal erythroid mitochondrial iron utilization. To clone the f gene, we used positional cloning techniques, and identified a frameshift mutation in a mitochondrial transmembrane protein. The mutated gene, Sfxn1, is the prototype of a novel family of evolutionarily conserved proteins present in eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Northern
  • Blotting, Western
  • Bone and Bones / abnormalities*
  • Cation Transport Proteins*
  • Cell Line
  • Cell Membrane / metabolism*
  • Cloning, Molecular
  • DNA Mutational Analysis
  • DNA, Complementary / metabolism
  • Frameshift Mutation
  • Humans
  • Membrane Proteins / biosynthesis
  • Membrane Proteins / genetics*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Mitochondria / metabolism*
  • Models, Genetic
  • Molecular Sequence Data
  • Open Reading Frames
  • Phenotype
  • Physical Chromosome Mapping
  • Sequence Homology, Amino Acid
  • Tissue Distribution


  • Cation Transport Proteins
  • DNA, Complementary
  • Membrane Proteins
  • Sfxn1 protein, mouse