Phenotype Image Detail

Image

Caption

Labeled corticospinal tract (CST) in wild-type and heterozygous (+/+ and +/o) and Epha4^tm1Byd/Epha4^tm1Byd (o/o) mice. A: Schematic representation of the corticospinal projection traced in mice. Multiple injections of the tracer were made in the motor cortex in the left cerebral hemisphere of adult mice. The labeled CST axons descend through the midbrain, pons, and pyramid in the medulla. In wild-type and heterozygous mice, the CST axons decussate at the medulla, crossing the midline traveling from left ventral to right dorsal, enter the dorsal funiculus of the spinal cord, and terminate predominantly in the dorsal horn contralateral to the tracer injections. In mutant mice, labeled CST axons appeared to terminate in the medulla and intermediate and ventral region of the spinal gray matter. Some labeled fibers were observed to recross the midline. B: Transverse sections of medulla showing the decussation of labeled CST fibers travelling from left ventral (v) to right dorsal (d). In mutant mice, many CST axons do not enter the dorsal column area. (Bar=450um). C and D: Transverse sections of cervical spinal cord showing area of dorsal funiculus (C) and dorsal horn (D). In wild-type mice, labeled CST axons terminate in the right dorsal horn (arrow). In mutants, axons project predominantly into the intermediate and ventral regions of the gray matter, and no labeled axons were observed terminating in the dorsal horn. cc, central canal; df, dorsal funiculus. (Bar = 125 um). E: Longitudinal sections of cervical spinal cord. CST axons in the right dorsal funiculus are seen in the midline. In mutants, some CST fibers recross the midline and project to the gray matter ipsilateral to the tracer injections. (Bar = 300um). F: Transverse sections of lumbar spinal cord. A reduced number of labeled CST axons was observed in the dorsal funiculus of the mutant mice compared with wild-type. (Bar = 125um)

Copyright

This image is from Dottori M, Proc Natl Acad Sci U S A 1998 Oct 27;95(22):13248-53. Copyright 1998 National Academy of Sciences, U.S.A. J:50573

Associated Alleles

Symbol	Name
Epha4^tm1Byd	Eph receptor A4; targeted mutation 1, Andrew W Boyd

Associated Genotypes

Allelic Composition	Genetic Background
Epha4^tm1Byd/Epha4^tm1Byd	involves: 129S1/Sv * C57BL/6