Dy. Fu et al., MOLECULAR-CLONING AND CHARACTERIZATION OF THE MOUSE DOPAMINE D-3 RECEPTOR GENE - AN ADDITIONAL INTRON AND AN MESSENGER-RNA VARIANT, DNA and cell biology, 14(6), 1995, pp. 485-492
The intron-exon organization for the murine dopamine D-3 receptor gene
was determined. A novel intron of approximately 1 kb was identified i
n both rat and mouse D-3 receptor genes. This intron (termed intron 4)
is situated between coding nucleotides 723 and 724, resulting in a sp
lit of former exon 4 (containing nucleotides 527-801) into two separat
e exons (exon 4 and exon 5). Thus, the coding regions of the D-2 and D
-3 receptor genes contain an identical number of exons (seven exons) a
nd share a very similar gene structure. Reverse transcription-PCR expe
riments revealed a short form of mouse D-3 mRNA (D-3Short) that lacks
the first 63 nucleotides from exon 6, and results from a splicing even
t occurring within this exon. However, this mRNA variant was not found
in either rat or human brain. No dopamine D-3 receptor mRNA variants
were found deriving from the alternative splicing of exon 5, although
its counterpart, exon 6 in the D-2 receptor gene, is spliced out to pr
oduce the D-2Short mRNA. These data suggest that, although the intron-
exon organizations of the D-2 and D-3 receptor genes are similar, the
encoded transcripts may be processed differently.