The distribution of heat shock proteins in the nervous system of the unstressed mouse embryo suggests a role in neuronal and non-neuronal differentiation.
Heat shock proteins (Hsps) act as molecular chaperones and are generally constitutively expressed in the absence of stress. Hsps are also inducible by a variety of stressors whose effects could be disastrous on the brain. It has been shown previously that Hsps are differentially expressed in glial and neuronal cells, as well as in the different structures of the brain. This differential expression has been related to specific functions distinct from their general chaperone function, such as intracellular transport. We investigated here the constitutive expression of 5 Hsps (the small Hsp, Hsp25, the constitutive Hsc70 and Hsp90beta, the mainly inducible Hsp70 and Hsp90alpha), and of a molecular chaperone, TCP-1alpha during mouse nervous system development. We analyzed, by immunohistochemistry, their distribution in the central nervous system and in the ganglia of the peripheral nervous system from day 9.5 (E9.5) to day 17.5 (E17.5) of gestation. Hsps are expressed in different cell classes (neuronal, glial, and vascular). The different proteins display different but often overlapping patterns of expression in different regions of the developing nervous system, suggesting unique roles at different stages of neural maturation. Their putative function in cell remodeling during migration or differentiation and in protein transport is discussed. Moreover we consider Hsp90 function in cell signaling and the role of Hsp25 in apoptosis protection.
Loones
M T
MT
Département de Biologie, UMR 8541, Ecole Normale Supérieure, Paris, France. loones@wotan.ens.fr
Chang
Y
Y
Morange
M
M
D000818:Animals; D001921:Brain / Q000196:embryology*; D002352:Carrier Proteins / Q000302:isolation & purification; D002454:Cell Differentiation; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000302:isolation & purification; D018841:HSP90 Heat-Shock Proteins / Q000302:isolation & purification; D006360:Heat-Shock Proteins / Q000302:isolation & purification*; D051379:Mice; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000302:isolation & purification; D009419:Nerve Tissue Proteins / Q000302:isolation & purification*; D009474:Neurons / Q000166:cytology; D014018:Tissue Distribution
D002352:Carrier Proteins; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; C494372:Hspa8 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins