TY - JOUR
T1 - Genes required for axon pathfinding and extension in the C. elegans nerve ring
AU - Zallen, Jennifer A.
AU - Kirch, Susan A.
AU - Bargmann, Cornelia I.
PY - 1999/8
Y1 - 1999/8
N2 - Over half of the neurons in Caenorhabditis elegans send axons to the nerve ring, a large neuropil in the head of the animal. Genetic screens in animals that express the green fluorescent protein in a subset of sensory neurons identified eight new sax genes that affect the morphology of nerve ring axons. sax-3/robo mutations disrupt axon guidance in the nerve ring, while sax-5, sax-9 and unc-44 disrupt both axon guidance and axon extension. Axon extension and guidance proceed normally in sax-1, sax-2, sax-6, sax-7 and sax-8 mutants, but these animals exhibit later defects in the maintenance of nerve ring structure. The functions of existing guidance genes in nerve ring development were also examined, revealing that SAX-3/Robo acts in parallel to the VAB-1/Eph receptor and the UNC-6/netrin, UNC-40/DCC guidance systems for ventral guidance of axons in the amphid commissure, a major route of axon entry into the nerve ring. In addition, SAX-3/Robo and the VAB-1/Eph receptor both function to prevent aberrant axon crossing at the ventral midline. Together, these genes define pathways required for axon growth, guidance and maintenance during nervous system development.
AB - Over half of the neurons in Caenorhabditis elegans send axons to the nerve ring, a large neuropil in the head of the animal. Genetic screens in animals that express the green fluorescent protein in a subset of sensory neurons identified eight new sax genes that affect the morphology of nerve ring axons. sax-3/robo mutations disrupt axon guidance in the nerve ring, while sax-5, sax-9 and unc-44 disrupt both axon guidance and axon extension. Axon extension and guidance proceed normally in sax-1, sax-2, sax-6, sax-7 and sax-8 mutants, but these animals exhibit later defects in the maintenance of nerve ring structure. The functions of existing guidance genes in nerve ring development were also examined, revealing that SAX-3/Robo acts in parallel to the VAB-1/Eph receptor and the UNC-6/netrin, UNC-40/DCC guidance systems for ventral guidance of axons in the amphid commissure, a major route of axon entry into the nerve ring. In addition, SAX-3/Robo and the VAB-1/Eph receptor both function to prevent aberrant axon crossing at the ventral midline. Together, these genes define pathways required for axon growth, guidance and maintenance during nervous system development.
KW - Axon growth
KW - Caenorhabditis elegans
KW - Guidance
KW - SAX-3/Robo
KW - UNC-40/DCC
KW - UNC-6/netrin
KW - VAB-1/Eph receptor
UR - http://www.scopus.com/inward/record.url?scp=0032849015&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032849015&partnerID=8YFLogxK
M3 - Article
C2 - 10409513
AN - SCOPUS:0032849015
VL - 126
SP - 3679
EP - 3692
JO - Journal of Embryology and Experimental Morphology
JF - Journal of Embryology and Experimental Morphology
SN - 0950-1991
IS - 16
ER -