These boundary cells act as a barrier so that neighboring cell populations do not mix, send instructions to progenitor cells of the adjacent rhombomere
, and act as a source of progenitors and neurons.
Krumlauf, "Role of a conserved retinoic acid response element in rhombomere
restriction of Hoxb-1," Science, vol.
Two main theories explain the disease to be due to an interruption in the vascular supply of the brainstem resulting in ischemia in the region of the facial cranial nerve nuclei owing to an environmental, mechanical, or a genetic cause [3-5] or an embryological developmental defect in the rhombomere
segments including the facial cranial nerve nuclei [6, 7].
In the latter case, the presence of facial motoneurons in only one rhombomere
might represent a modification specific to amphibians.
Late effects of retinoic acid on neural crest and aspects of rhombomere
Cadherin-6 expression transiently delineates specific rhombomeres
, other neural tube subdivisions, and neural crest subpopulations in mouse embryos.
pattern the rhombomeres
and pharyngeal arches, or tissue primordia that
They migrate toward specific directions, sometimes traversing across brain compartments such as rhombomeres
(PN neurons and facial branchiomotor neurons) or pallium-subpallium boundaries (cortical interneurons).
Horigome, "Developmental morphology of branchiomeric nerves in a cat shark, Scyliorhinus torazame, with special reference to rhombomeres
, cephalic mesoderm, and distribution patterns of cephalic crest cells," Zoological Science, vol.
This bidirectional Eph/ ephrin signaling between cells is fundamentally involved in developmental processes that require organized patterning and movement of cells, such as axonal guidance, patterning of hindbrain rhombomeres
, and maintenance of cellular boundaries in the development of the central nervous system (3) or in the remodeling of blood vessels (4).
Developmental differences also exist for Abd motoneurons, as the abducens nucleus originates from embryonic rhombomeres
(Rhs) 5 and 6 for most vertebrates, including lampreys, teleosts, birds, and reptiles (1), and exclusively from Rhs 5 in frogs (16) and mammals (1).
The vertebrate hindbrain is subdivided into a series of compartments called rhombomeres
. During development of the hindbrain certain genes are expressed to differentiate the compartments.