Alternative splicing and dopamine D2 receptor diversity.
Item
-
Title
-
Alternative splicing and dopamine D2 receptor diversity.
-
Identifier
-
AAI9417509
-
identifier
-
9417509
-
Creator
-
Snyder, Lenore Anne.
-
Contributor
-
Adviser: James Roberts
-
Date
-
1994
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Biology, General | Biology, Neuroscience
-
Abstract
-
Molecular cloning has led to the identification of three genes, termed D2, D3, and D4, which encode receptors of the dopamine D2 family. Alternative mRNA processing of these intron-containing genes generates a diversity of dopamine receptors and truncated receptor variants.;In the present studies, an mRNA variant of the originally published D2 receptor was identified by polymerase chain reaction. The receptor encoded by this transcript (which we named D2L) differed from the reported D2 receptor (renamed D2S) by the presence of an additional 29 amino acids within the third cytoplasmic loop. The reported D2 receptor gene structure indicated that D2L and D2S were alternative mRNA splice variants.;To gain insight into the biological roles of the isoforms, the distribution and relative abundance of D2L and D2S mRNA were mapped in the rat brain and pituitary using a quantitative solution hybridization/nuclease protection assay. The results of this study indicated that both isoforms were present in all tissues examined, with D2L mRNA in greater abundance.;To investigate the signaling of D2L and D2S, the two receptors were expressed in AtT20 and GH3 cells. The modulation of calcium influx was studied using the calcium sensitive fluorescent dye, fluo-3. In both cell types, the activation of either isoform led to a reduction in calcium influx stimulated by the L-type calcium channel agonist BayK 8644. The responses mediated by both isoforms were similarly attenuated by pertussis toxin, indicating coupling to G-proteins of the Go/Gi family.;Using PCR, a variant of the rat D3 receptor was identified in which the region encoding the first extracellular loop and the third transmembrane domain was deleted. The reported gene structure of the rat D3 receptor indicated that this variant was produced by alternative mRNA splicing. The identified transcript encoded a truncated form of the D3 receptor containing the amino terminal portion of the receptor through the second transmembrane domain, followed by 19 novel amino acids. A similar deletion variant of the D3 receptor was identified in the human. The biological significance of these D3 receptor variants has not been determined.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
