Phenotype Image Detail

Image

Caption

Amyelinating peripheral neuropathies in Lama4^tm1Ktry/Lama4^tm1Ktry and Lama2^dy-2J/Lama2^dy-2J mice. A-D: Overlapping postural defects. When suspended, wild-type (wt,A) mice extend limbs downward, whereas Lama4^tm1Ktry/Lama4^tm1Ktry (Lama4^-/-) mice retract and then extend hindlimbs backward (B and C). Lama2^dy-2J/Lama2^dy-2J (Lama2^dy2J) mice retract hindlimbs at juvenile ages (D, 4 wk), before the onset of permanent contractures (E, 3 mo). F-J: Toluidine blue-stained resin sections of adult control (F), Lama4^tm1Ktry/Lama4^tm1Ktry (G and H), and Lama2^dy-2J/Lama2^dy-2J (I and J) sciatic nerves at low (F,G, and I) and high (H and J) magnification. Bundles of unsheathed axons are present in mutants, but not controls. K-O: Electron micrographs show most bundles lack intervening Schwann cell processes. Some Lama4^tm1Ktry/Lama4^tm1Ktry Schwann cells along large bundles establish promyelinating relations with single axons (K, asterisk), but usually myelinate small bundles altogether (L and M). Some polyaxonal myelination included intervening Schwann cell processes (M, arrows), possibly from adjacent cells along the nerve. In Lama2^dy-2J/Lama2^dy-2J, polyaxonal myelination was rare (O, left), but large rafts of partially defasciculated, unmyelinated, mixed caliber fibers were common (O, right). Bar in F, 38 um (F,G, and I); 15 um (H and J); 3 um (K,L,N and O); 1.8 um (M).

Copyright

This image is from Yang D, J Cell Biol 2005 Feb 14;168(4):655-66, and is displayed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. J:98086

Associated Alleles

Symbol	Name
Lama2^dy-2J	laminin, alpha 2; dystrophia muscularis 2 Jackson
Lama4^tm1Ktry	laminin, alpha 4; targeted mutation 1, Karl Tryggvason

Associated Genotypes

Allelic Composition	Genetic Background
Lama4^tm1Ktry/Lama4^tm1Ktry	B6.129X1-Lama4^tm1Ktry
Lama2^dy-2J/Lama2^dy-2J	B6.WK-Lama2^dy-2J/J