Annexin IV is a marker of roof and floor plate development in the murine CNS.
Midline structures, such as the notochord and floor plate, are crucial to the developing central nervous system (CNS). Previously, we demonstrated that annexin IV is an excellent marker of midline structures. In the present study, we explore the possible role of annexin IV in development of the CNS midline. Using immunocytochemistry with an antibody to annexin IV, we have elucidated the temporal and spatial expression of this molecule. Annexin IV is present in the notochord at embryonic day (E) 8.5, prior to its expression in any structures within the neural tube. Subsequently, annexin IV is expressed by floor plate cells at E9.5. Annexin IV is also expressed in the roof plate, but not until E10.5. To determine if normal morphogenesis of these midline structures is essential for annexin IV expression, we analyzed two strains of mutant mice that have defective formation of either the floor or the roof plate. In Danforth's short-tail mice, the floor plate is absent from the caudal spinal cord, and annexin IV immunopositivity disappears at the level where the floor plate is missing. In curly tail mutant mice, there can be a failure of the neural tube to close, and in these regions there is no annexin IV expression in presumptive roof plate cells. Finally, annexin IV immunolabeling is present from the caudal spinal cord, through the brainstem up to the diencephalon and lamina terminalis. Thus, annexin IV is an excellent marker for differentiated midline cells, is temporally and spatially correlated with development of the floor and roof plates, and is expressed in a rostral-caudal manner that supports the hypothesis that the floor plate extends the full length of the original neural tube.
Hemre
K M
KM
Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis 38163, USA.
Keller-Peck
C R
CR
Campbell
R M
RM
Peterson
A C
AC
Mullen
R J
RJ
Goldowitz
D
D
D000818:Animals; D017314:Annexin A4 / Q000032:analysis*; D015415:Biomarkers / Q000737:chemistry; D002490:Central Nervous System / Q000737:chemistry* / Q000196:embryology; D007150:Immunohistochemistry; D051379:Mice; D008813:Mice, Inbred ICR; D009672:Notochord / Q000737:chemistry* / Q000196:embryology
D017314:Annexin A4; D015415:Biomarkers