Cloning and differentiation-induced expression of a murine serotonin1A receptor in a septal cell line.
A neuronal cell model endogenously expressing the 5-HT1A receptor, in which to study the function and regulation of this gene, has yet to be identified. We examined murine SN-48 cells, a septum x neuroblastoma fusion cell line that proliferates in a nondifferentiated state but can be induced to differentiate into neurofilament-positive cells following 24-96 hr treatment with 10 microM retinoic acid in low serum. Northern blot analysis demonstrated the presence of a single 10.9 kilobase (kb) 5-HT1A receptor RNA species in differentiated SN-48 cells, which was not detected in undifferentiated SN-48 cells. The presence of receptor RNA in differentiated SN-48 cells correlated with the appearance of functional responses (i.e., pertussis toxin-sensitive inhibition of cAMP accumulation) to 5-HT1A agonists in differentiated but not in undifferentiated cells. In order to verify that the large 10.9 kb RNA species in SN-48 cells truly corresponded to the mouse 5-HT1A receptor RNA, a cDNA fragment from differentiated SN-48 cells was used to clone the corresponding mouse brain cDNA. The 2.4 kb cDNA contained a single open reading frame that displayed high (> 85% predicted amino acid identity) homology to the human and rat 5-HT1A receptor genes. When transfected into receptor-negative Ltk- cells, this cDNA was found to direct expression of a murine 5-HT1A receptor. Thus, we conclude that upon differentiation SN-48 cells express RNA encoding functional 5-HT1A receptors. The SN-48 septal cells will provide a useful cellular model system for investigating aspects of neuronal differentiation leading to the development of sensitivity to serotonergic input.
Charest
A
A
Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
Wainer
B H
BH
Albert
P R
PR
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D003001:Cloning, Molecular; D015870:Gene Expression; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009447:Neuroblastoma / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011985:Receptors, Serotonin / Q000235:genetics* / Q000378:metabolism*; D012686:Septal Nuclei / Q000166:cytology / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D011985:Receptors, Serotonin; D014212:Tretinoin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin