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Global defects in collagen secretion in a Mia3/TANGO1 knockout mouse.

Wilson DG, Phamluong K, Li L, Sun M, Cao TC, Liu PS, Modrusan Z, Sandoval WN, Rangell L, Carano RA, Peterson AS, Solloway MJ - J. Cell Biol. (2011)

Bottom Line: These changes are associated with intracellular accumulation of collagen and the induction of a strong unfolded protein response, primarily within the developing skeleton.Chondrocyte maturation and bone mineralization are severely compromised in Mia3- embryos, leading to dwarfism and neonatal lethality.Thus, Mia3's role in protein secretion is much broader than previously realized, and it may, in fact, be required for the efficient secretion of all collagen molecules in higher organisms.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Biology, Genentech, South San Francisco, CA 94080, USA.

ABSTRACT
Melanoma inhibitory activity member 3 (MIA3/TANGO1) [corrected] is an evolutionarily conserved endoplasmic reticulum resident transmembrane protein. Recent in vitro studies have shown that it is required for the loading of collagen VII, but not collagen I, into COPII-coated transport vesicles. In this paper, we show that mice lacking Mia3 are defective for the secretion of numerous collagens, including collagens I, II, III, IV, VII, and IX, from chondrocytes, fibroblasts, endothelial cells, and mural cells. Collagen deposition by these cell types is abnormal, and extracellular matrix composition is compromised. These changes are associated with intracellular accumulation of collagen and the induction of a strong unfolded protein response, primarily within the developing skeleton. Chondrocyte maturation and bone mineralization are severely compromised in Mia3- embryos, leading to dwarfism and neonatal lethality. Thus, Mia3's role in protein secretion is much broader than previously realized, and it may, in fact, be required for the efficient secretion of all collagen molecules in higher organisms.

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Mia3−/− embryos are dwarfed, edemic, and fail to form a mineralized skeleton. (A and B) Mia3 mutant embryos display a shortening of the snout and limbs at 16.5 dpc. (C and D) Mia3 mutant embryos are significantly dwarfed at 18.5 dpc. (E and F) Alizarin red–positive skeletal mineralization initiates within the intramembranous bone of the jaw and endochondral bones of the clavicles of 13.5-dpc wt embryos (arrows) but is absent from the Alcian blue–positive cartilage anlagen of Mia3 mutants. (G and H) Mineralization is advanced in nearly all axial and appendicular elements in 15.5-dpc control embryos but is profoundly delayed in the Mia3- skeleton. (I–L) Calcified matrix is apparent in the bones of 18.5-dpc knockout animals (I and J), but micro-CT (n = 3) maximum intensity projections highlight complete absence of the mature ossified skeleton (K and L). Bars, 1 mm.
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fig2: Mia3−/− embryos are dwarfed, edemic, and fail to form a mineralized skeleton. (A and B) Mia3 mutant embryos display a shortening of the snout and limbs at 16.5 dpc. (C and D) Mia3 mutant embryos are significantly dwarfed at 18.5 dpc. (E and F) Alizarin red–positive skeletal mineralization initiates within the intramembranous bone of the jaw and endochondral bones of the clavicles of 13.5-dpc wt embryos (arrows) but is absent from the Alcian blue–positive cartilage anlagen of Mia3 mutants. (G and H) Mineralization is advanced in nearly all axial and appendicular elements in 15.5-dpc control embryos but is profoundly delayed in the Mia3- skeleton. (I–L) Calcified matrix is apparent in the bones of 18.5-dpc knockout animals (I and J), but micro-CT (n = 3) maximum intensity projections highlight complete absence of the mature ossified skeleton (K and L). Bars, 1 mm.

Mentions: Mice carrying a single targeted allele (Mia3+/−) are fertile and show no gross evidence of haploinsufficiency. Homozygous mice, although recovered in the expected Mendelian frequencies, exhibit short-limbed dwarfism and die at birth (100% penetrant; Table I). Neonates fail to breathe and are often edemic with subdermal microhemorrhages. Skin and other tissues were noted to be particularly fragile during dissection. Mia3−/− embryos first appear morphologically distinct at 15.5–16.5 dpc (Fig. 2, A and B) with shortening of the snout and limbs, a subtle reduction in stature, and apparent tightening of the normally wrinkled dermis. These hallmarks of the mutant phenotype are preserved at 18.5 dpc, and the body axis is further shortened by ∼50% respective to controls (Fig. 2, C and D). Alizarin red/Alcian blue–stained skeletal preparations show that relative position and numbers of skeletal elements are normal, but a delay in the onset of mineralization is apparent at 13.5 dpc (Fig. 2, E and F), and there is an almost complete lack of calcium deposits at 15.5 dpc (Fig. 2, G and H), a time when the majority of skeleton components have initiated primary mineralization.


Global defects in collagen secretion in a Mia3/TANGO1 knockout mouse.

Wilson DG, Phamluong K, Li L, Sun M, Cao TC, Liu PS, Modrusan Z, Sandoval WN, Rangell L, Carano RA, Peterson AS, Solloway MJ - J. Cell Biol. (2011)

Mia3−/− embryos are dwarfed, edemic, and fail to form a mineralized skeleton. (A and B) Mia3 mutant embryos display a shortening of the snout and limbs at 16.5 dpc. (C and D) Mia3 mutant embryos are significantly dwarfed at 18.5 dpc. (E and F) Alizarin red–positive skeletal mineralization initiates within the intramembranous bone of the jaw and endochondral bones of the clavicles of 13.5-dpc wt embryos (arrows) but is absent from the Alcian blue–positive cartilage anlagen of Mia3 mutants. (G and H) Mineralization is advanced in nearly all axial and appendicular elements in 15.5-dpc control embryos but is profoundly delayed in the Mia3- skeleton. (I–L) Calcified matrix is apparent in the bones of 18.5-dpc knockout animals (I and J), but micro-CT (n = 3) maximum intensity projections highlight complete absence of the mature ossified skeleton (K and L). Bars, 1 mm.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3105544&req=5

fig2: Mia3−/− embryos are dwarfed, edemic, and fail to form a mineralized skeleton. (A and B) Mia3 mutant embryos display a shortening of the snout and limbs at 16.5 dpc. (C and D) Mia3 mutant embryos are significantly dwarfed at 18.5 dpc. (E and F) Alizarin red–positive skeletal mineralization initiates within the intramembranous bone of the jaw and endochondral bones of the clavicles of 13.5-dpc wt embryos (arrows) but is absent from the Alcian blue–positive cartilage anlagen of Mia3 mutants. (G and H) Mineralization is advanced in nearly all axial and appendicular elements in 15.5-dpc control embryos but is profoundly delayed in the Mia3- skeleton. (I–L) Calcified matrix is apparent in the bones of 18.5-dpc knockout animals (I and J), but micro-CT (n = 3) maximum intensity projections highlight complete absence of the mature ossified skeleton (K and L). Bars, 1 mm.
Mentions: Mice carrying a single targeted allele (Mia3+/−) are fertile and show no gross evidence of haploinsufficiency. Homozygous mice, although recovered in the expected Mendelian frequencies, exhibit short-limbed dwarfism and die at birth (100% penetrant; Table I). Neonates fail to breathe and are often edemic with subdermal microhemorrhages. Skin and other tissues were noted to be particularly fragile during dissection. Mia3−/− embryos first appear morphologically distinct at 15.5–16.5 dpc (Fig. 2, A and B) with shortening of the snout and limbs, a subtle reduction in stature, and apparent tightening of the normally wrinkled dermis. These hallmarks of the mutant phenotype are preserved at 18.5 dpc, and the body axis is further shortened by ∼50% respective to controls (Fig. 2, C and D). Alizarin red/Alcian blue–stained skeletal preparations show that relative position and numbers of skeletal elements are normal, but a delay in the onset of mineralization is apparent at 13.5 dpc (Fig. 2, E and F), and there is an almost complete lack of calcium deposits at 15.5 dpc (Fig. 2, G and H), a time when the majority of skeleton components have initiated primary mineralization.

Bottom Line: These changes are associated with intracellular accumulation of collagen and the induction of a strong unfolded protein response, primarily within the developing skeleton.Chondrocyte maturation and bone mineralization are severely compromised in Mia3- embryos, leading to dwarfism and neonatal lethality.Thus, Mia3's role in protein secretion is much broader than previously realized, and it may, in fact, be required for the efficient secretion of all collagen molecules in higher organisms.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Biology, Genentech, South San Francisco, CA 94080, USA.

ABSTRACT
Melanoma inhibitory activity member 3 (MIA3/TANGO1) [corrected] is an evolutionarily conserved endoplasmic reticulum resident transmembrane protein. Recent in vitro studies have shown that it is required for the loading of collagen VII, but not collagen I, into COPII-coated transport vesicles. In this paper, we show that mice lacking Mia3 are defective for the secretion of numerous collagens, including collagens I, II, III, IV, VII, and IX, from chondrocytes, fibroblasts, endothelial cells, and mural cells. Collagen deposition by these cell types is abnormal, and extracellular matrix composition is compromised. These changes are associated with intracellular accumulation of collagen and the induction of a strong unfolded protein response, primarily within the developing skeleton. Chondrocyte maturation and bone mineralization are severely compromised in Mia3- embryos, leading to dwarfism and neonatal lethality. Thus, Mia3's role in protein secretion is much broader than previously realized, and it may, in fact, be required for the efficient secretion of all collagen molecules in higher organisms.

Show MeSH
Related in: MedlinePlus