Spatiotemporal expression patterns of slit and robo genes in the rat brain.
Diffusible chemorepellents play a major role in guiding developing axons toward their correct targets by preventing them from entering or steering them away from certain regions. Genetic studies in Drosophila revealed a repulsive guidance system that prevents inappropriate axons from crossing the central nervous system midline; this repulsive system is mediated by the secreted extracellular matrix protein Slit and its receptors Roundabout (Robo). Three distinct slit genes (slit1, slit2, and slit3) and three distinct robo genes (robo1, robo2, rig-1) have been cloned in mammals. However, to date, only Robo1 and Robo2 have been shown to be receptors for Slits. In rodents, Slits have been shown to function as chemorepellents for several classes of axons and migrating neurons. In addition, Slit can also stimulate the formation of axonal branches by some sensory axons. To identify Slit-responsive neurons and to help analyze Slit function, we have studied, by in situ hybridization, the expression pattern of slits and their receptors robo1 and robo2, in the rat central nervous system from embryonic stages to adult age. We found that their expression patterns are very dynamic: in most regions, slit and robo are expressed in a complementary pattern, and their expression is up-regulated postnatally. Our study confirms the potential role of these molecules in axonal pathfinding and neuronal migration. However, the persistence of robo and slit expression suggests that the couple slit/robo may also have an important function in the adult brain.
Marillat
Valérie
V
INSERM U106, Bâtiment de Pédiatrie, Hôpital de la Salpêtrière, 75013 Paris, France.
Cases
Oliver
O
Nguyen-Ba-Charvet
Kim Tuyen
KT
Tessier-Lavigne
Marc
M
Sotelo
Constantino
C
Chédotal
Alain
A
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000166:cytology / Q000196:embryology* / Q000254:growth & development; D002448:Cell Adhesion / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics*; D002633:Chemotaxis / Q000235:genetics; D004027:Diencephalon / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D005260:Female; D005333:Fetus; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006023:Glycoproteins; D020439:Growth Cones / Q000378:metabolism* / Q000648:ultrastructure; D008636:Mesencephalon / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009833:Olfactory Pathways / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D011247:Pregnancy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D011971:Receptors, Immunologic / Q000235:genetics*; D012249:Rhombencephalon / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D013687:Telencephalon / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D000097905:Roundabout Proteins
D006023:Glycoproteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D000097905:Roundabout Proteins; C120566:slit protein, vertebrate