Carpenter EM, Goddard JM, Chisaka O, Manley NR, Capecchi MR:
Loss of Hox-A1 (Hox-1.6) function results in the reorganization of
the murine hindbrain.
Development 1993 Aug;118(4):1063-75
ABSTRACT
Targeted disruption of the murine hox-A1 gene results in severe
defects in the formation of the hindbrain and associated cranial
ganglia and nerves. Carbocyanine dye injections were used to trace
afferent and efferent projections to and from the hindbrain in
hox-A1-/hox-A1- mutant mice. Defects were observed in the position
of efferent neurons in the hindbrain and in their projection
patterns. In situ hybridization was used to analyze the
transcription pattern of genes expressed within specific
rhombomeres. Krox-20, int-2 (fgf-3), and hox-B1 all display aberrant
patterns of expression in hox-A1- mutant embryos. The observed
morphological and molecular defects suggest that there are changes
in the formation of the hindbrain extending from rhombomere 3
through rhombomere 8 including the absence of rhombomere 5. Also,
motor neurons identified by their axon projection patterns which
would normally be present in the missing rhombomere appear to be
respecified to or migrate into adjacent rhombomeres, suggesting a
role for hox-A1 in the specification of cell identity and/or cell
migration in the hindbrain.
