CeSERT genes, proteins, and modulatory compounds
The invention features substantially pure nucleic acid sequences encoding wild-type or mutant serotonin retake transporter (SERT) polypeptides, as well as the polypeptides themselves. The invention also features methods for identifying modulators of the biological activity of a SERT and for identifying if such a modulator has a secondary target. In addition, the invention features methods for treating a condition in a subject.
1. A method for determining whether a test compound, which modulates the uptake of serotonin by a serotonin reuptake transporter (SERT), has an effect on a secondary target, said method comprising the steps of:
(a) contacting a Caenorhabditis elegans nematode lacking a wild-type SERT polypeptide and expressing a mutated Caenorhabditis elegans SERT (CeSERT) polypeptide selected from the group consisting of a CeSERT(n822) polypeptide, a CeSERT(n823) polypeptide, and a CeSERT(n3314) polypeptide with said compound, wherein said mutated CeSERT polypeptide has a reduced capacity to take up serotonin relative to wild-type; and
(b) analyzing said nematode for an effect of said contacting on a defined behavior by said nematode, wherein a difference in said defined behavior by said nematode, relative to said defined behavior by a Caenorhabditis elegans nematode expressing a mutated CeSERT polypeptide but not contacted with said compound, indicates said compound has an effect on a secondary target.
2. The method of claim 1 , wherein steps (a) and (b) are repeated using a Caenorhabditis elegans nematode selected from at least two Caenorhabditis elegans nematodes expressing a mutated CeSERT polypeptide selected from the group consisting of a CeSERT(n822) polypeptide, a CeSERT(n823) polypeptide, and a CeSERT(n3314) polypeptide, wherein said mutated CeSERT polypeptide differs from said mutated CeSERT polypeptide of step (a).
3. The method of claim 1 , wherein said mutated CeSERT polypeptide is a complete loss-of-function.
4. The method of claim 1 , wherein said method comprises a liquid locomotion assay.
5. The method of claim 1 , wherein said defined behavior is movement, pharyngeal pumping, egg-laying, nose contraction, or defecation.
6. The method of claim 1 , wherein said compound is from a class of compounds selected from the group consisting of antidepressants, migraine medications, and anti-emetics.
7. The method of claim 6 , wherein said antidepressant is a selective serotonin reuptake inhibitor.
8. The method of claim 6 , wherein said antidepressant is a tricyclic antidepressant.
9. The method of claim 6 , wherein said antidepressant is a monoamine oxidase inhibitor.
10. The method of claim 1 , wherein said test compound is administered at more than one concentration.