Fuminori Yamaguchi

Molecular cloning of 5-hydroxytryptamine (5-HT) type 1 receptor genes from the Japanese puffer fish, Fugu rubripes

To characterize the structure of Fugu G-protein coupled receptor family and its evolutionary divergence, we have cloned and sequenced the Fugu 5-HT type 1 receptor genes by Polymerase Chain Reaction (PCR) with degenerate primers followed by phage library screening. The analysis of the deduced amino acid sequences showed that F1A alpha and F1A beta have the highest homology to the human 5-HT1A receptor (71.5% and 63.7%, respectively). Another clone, F1D, showed highest (70.5%) homology to the human type 1D receptor. The amino acid residues that are important for ligand binding have been conserved in these Fugu genes. The phylogenetic tree analysis suggests that the duplication event of the Fugu type 1A receptor may have occurred after the divergence of Fugu and the tetrapod lineage.

MOLECULAR CLONING OF EDG-3 AND N-SHC GENES FROM THE PUFFER FISH, FUGU RUBRIPES, AND CONSERVATION OF SYNTENY WITH THE HUMAN GENOME

EDG‐3 is a receptor for sphingosine‐1‐phosphate mapped on human chromosome 9q22.1–q22.2. We used the compact Fugu genome for its linkage analysis. The Fugu EDG‐3 was composed of one intron and two exons, encoding a 384 amino acid protein that has 56.9% homology with the human EDG‐3. Approximately 3 kb apart, a neuronal Shc (N‐Shc) gene was identified. It spans 7 kb containing 12 coding exons, and has an overall 53.4% similarity with the human protein. We mapped the human N‐Shc gene to chromosome 9q21.3–q22.2. This is the first report of the genomic structure and the linkage of these two genes conserved between Fugu and human.

Analysis of Dopamine and Neuropeptides in 6-OHDA-Lesioned Rats

Cholecystokinin (CCK) and dopamine (DA) coexist in the ventral tegmental area and medial substantia nigra neurons.1 In the brain of Parkinson’s disease patients, a prominent decrease in CCK content of the substantia nigra has been reported,2 and it is thought that DA and CCK might be related to the etiology of Parkinson’s disease. The precise functional interaction between DA and CCK, however, is not clarified. Based on the hypothesis that CCK has a functional role as one of the modulators of DA metabolism, ceruletide (CLT), which is a CCK-related decapeptide, is currently under trial for the treatment of diseases with involuntary movements including Parkinson’s disease.3 In the present study we attempted to clarify the mechanism of action of CLT and CCK with respect to their receptors as well as their effect on behavior in a Parkinson’s disease model, namely, the 6-OHDA unilaterally lesioned rat.