eral nervous system, the aCC motoneuron can be 
misrouted, demonstrating that misexpression of fas- 
ciclin II can alter growth cone guidance. 
A highly sensitive genetic assay has been estab- 
lished to screen for genes that encode products that 
interact with fas II. The assay utilizes a mutation 
that reduces the amount of fasciclin II protein to just 
the minimal amount required to generate certain 
sensory organs. This assay is used to screen for genes 
in which a 50% reduction in their protein level re- 
sults in a failure of these sensory organs to form. One 
such gene is the abelson tyrosine kinase. 
Mutations That Affect Motoneuron Guidance 
and Muscle Target Recognition 
A model system for the study of both pathway and 
target recognition is based on the ability of motoneu- 
ron growth cones to find and recognize their correct 
muscles. Using an antibody that selectively stains 
the growth cones and axons of nearly all motoneu- 
rons, members of the Goodman laboratory have em- 
barked on a systematic screen for mutations that af- 
fect motoneuron guidance and muscle target 
recognition. Thus far, over 3,000 mutagenized lines 
have been screened for the second chromosome. 
Many new mutants have been isolated that perturb 
the projection of motoneuron growth cones, includ- 
ing some that affect the development of specific 
motor axon pathways, some that perturb the forma- 
tion of motor branches to specific muscles, and 
some that affect the recognition of specific muscle 
targets. 
In other projects Dr. Goodman and his colleagues 
are studying the function of connectin during neuro- 
muscular target recognition; of genes expressed by 
subsets of glia; of fasciclin IV during growth cone 
guidance in the grasshopper limb bud; of laminin A 
in the guidance of sensory axon projections and 
imaginal disc morphogenesis; and of the fat and 
dachsous cadherins in tissue morphogenesis and 
cell proliferation. (Studies on comm, connectin, 
and some of those on fas II are supported by grants 
from the National Institutes of Health.) 
Dr. Goodman is also Professor of Neurobiology 
in the Department of Molecular and Cell Biology 
at the University of California, Berkeley, and Ad- 
junct Professor in the Department of Physiology 
at the University of California School of Medicine, 
San Francisco. 
Books and Chapters of Books 
Goodman, C.S., Grenningloh, G., and Bieber, A.J. 
1991. Molecular genetics of neural cell adhesion 
molecules in Drosophila. In The Nerve Growth 
Cone (Letourneau, P.C., Kater, S.B., and Ma- 
cagno, E.R., Eds.). New York: Raven, pp 283- 
301. 
Articles 
Freeman, M., Klambt, C., Goodman, C.S., and Ru- 
bin, G.M. 1992. The argos gene encodes a diffu- 
sible factor that regulates cell fate decisions in the 
Drosophila eye. Cell 69:963-975. 
Grenningloh, G., and Goodman, C.S. 1992. Path- 
way recognition by neuronal growth cones: ge- 
netic analysis of neural cell adhesion molecules 
in Drosophila. Curr Opin Neurobiol 2:42-47. 
Grenningloh, G., Rehm, E.J., and Goodman, C.S. 
1991. Genetic analysis of growth cone guidance 
in Drosophila: fasciclin II functions as a neuronal 
recognition molecule. Cell 67:45-57 . 
Hortsch, M., and Goodman, C.S. 1991. Cell and 
substrate adhesion molecules in Drosophila. 
Annu Rev Cell Biol 7:505-557. 
Klambt, C. , and Goodman, C.S. 1991. Role of mid- 
line glia and neurons in the formation of the axon 
commissures in the central nervous system of the 
Drosophila embryo. Ann N YAcad 5c/633:l42- 
159. 
Mahoney, P.A., Weber, U., Onofrechuck, P., Biess- 
mann, H., Bryant, P.J., and Goodman, C.S. 1991. 
The fat tumor suppressor gene in Drosophila en- 
codes a novel member of the cadherin gene su- 
perfamily. Cell 67:855-868. 
McAllister, L., Goodman, C.S., and Zinn, K. 1992. 
Dynamic expression of the cell adhesion mole- 
cule fasciclin I during embryonic development in 
Drosophila. Development 115:267-276. 
McAllister, L., Rehm, E.J., Goodman, C.S., and 
Zinn, K. 1992. Alternative splicing of micro- 
exons creates multiple forms of the insect cell 
adhesion molecule fasciclin I. / Neurosci 
12:895-905. 
Mlodzik, M., Hiromi, Y., Goodman, C.S., and Ru- 
bin, G.M. 1992. The presumptive R7 cell of the 
developing Drosophila eye receives positional 
information independent of sevenless, boss and 
sina. Mech Dev 37:37-42. 
Nose, A., Mahajan, V.B., and Goodman, C.S. 1992. 
Connectin: a hemophilic cell adhesion molecule 
expressed on a subset of muscles and the moto- 
neurons that innervate them in Drosophila. Cell 
70:553-567. 
Patel, N.H., Ball, E E., and Goodman, C.S. 1992. 
Changing role of even-skipped during the evo- 
lution of insect pattern formation. Nature 
357:339-342. 
NEUROSCIENCE 401 
