Tetratricopeptide Repeat Domain 7 in Psoriasis
Title: The tetratricopeptide repeat domain 7
gene is mutated in flaky skin mice: a model for psoriasis, autoimmunity,
Authors: Helms C, et al.
Publication: Exp Biol Med (Maywood). 2005 Oct;230(9):659-67.s
The flaky skin mutation called fsn in mice caused multiple abnormalities
including psoriatic-like lesions, anemia, hyper IgE, and the presence
of antibodies against double-stranded DNA resembling those detected
in systemic lupus erythematosus.
The fsn mutation was genetically mapped to a particular location
on chromosome 17, between D17Mit130 and D17M162. When this region
was sequenced, it was found that the mutation was due to insertion
of an endogenous retrovirus into one of the exons or coding regions
of the gene. This region encoded a tetratricopeptide repeat (TPR)
domain 7 or Ttc7 gene. This mutation caused reduction in the level
of Ttc7 mRNA, which was used to make TTC7 protein, as well as
insertion of abnormal amino acids that might affect its interaction
with other proteins.
The Ttc7 gene was expressed in multiple tissue types, including
the skin, kidney, spleen, and thymus. It was most abundant in
germinal center B cells and hematopoietic cells (those involved
in the formation of blood cells).
The authors suggested that Ttc7 mutation should be investigated
further for its role in immune system and blood disorders.
Editor’s Note: Hyper IgE is a rare immunodeficiency
disorder characterized by recurring skin infection by the staphylococcal
bacteria, lung infection, atopic dermatitis or eczema, and high
blood serum level of IgE.
Systemic lupus erythematosus (SLE) is an autoimmune disorder,
where the body’s immune system turns against parts of the
body it is supposed to protect. In SLE, or commonly referred as
just lupus, the immune system attacks and cause inflammation in
the joints, skin, kidney, heart, lungs, blood vessels and brain.