PT  - JOURNAL ARTICLE
AU  - WW Walthall
AU  - JA Plunkett
TI  - Genetic transformation of the synaptic pattern of a motoneuron class in Caenorhabditis elegans
AID  - 10.1523/JNEUROSCI.15-02-01035.1995
DP  - 1995 Feb 01
TA  - The Journal of Neuroscience
PG  - 1035--1043
VI  - 15
IP  - 2
4099  - http://www.jneurosci.org/content/15/2/1035.short
4100  - http://www.jneurosci.org/content/15/2/1035.full
SO  - J. Neurosci.1995 Feb 01; 15
AB  - Caenorhabditis elegans possesses two classes of inhibitory locomotory neurons, the DD and VD motoneurons (mns), and they form complementary components of a cross-inhibitory neuronal network innervating dorsal and ventral body muscles. The DD and VD mns (collectively called the D mns) share a number of morphological and neurochemical features, and mutations in a number of different genes disrupt both cell types in identical ways; however, the DD and VD mns have different lineal origins and different synaptic patterns. Given the number of phenotypic features shared by the D mns, it was of interest to determine what is responsible for the synaptic patterns that distinguish them. An analysis of the locomotory defect along with a genetic epistasis test suggested that unc-55 mutations alter the function of the VD but not the DD mns. Correlated with the defective locomotory behavior of unc-55 mutants was an alteration in the distribution of varicosities, structures associated with presynaptic elements, on the VD mns. The pattern of varicosities of the unc-55 VD mns resembled that of the wild- type DD mns. Moreover, the selective removal of the DD mns revealed that unc-55 VD mns had adopted a functional role appropriate for the DD mns. Thus, unc-55 appears to be involved in producing the synaptic patterns that distinguish the two D mn classes from one another; when the gene is mutated the VD and DD mns become structurally similar and functionally equivalent.