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Alternative non‐coding exons support serotonin transporter mRNA expression in the brain and gut
Author(s) -
Ozsarac N.,
Santha E.,
Hoffman B. J.
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2002.00964.x
Subject(s) - exon , biology , splice , alternative splicing , untranslated region , tandem exon duplication , exon trapping , microbiology and biotechnology , coding region , genetics , serotonin transporter , messenger rna , intron , splice site mutation , gene , rna splicing , complementary dna , genotype , rna
A number of studies in recent years have linked polymorphisms within the serotonin transporter (5HTT) gene to affective disorders and anxiety traits. The human 5HTT mRNA is alternatively spliced, and the splice variants are equally expressed in the human placental cell line and dorsal raphe. In this study, using 5′ rapid amplification of cDNA ends, we show that the rat 5HTT mRNA is alternatively spliced, leading to three distinct mRNAs differing in the 5′ untranslated region. To determine whether the three alternatively spliced mRNA species that contain one of the following untranslated regions (i) exon 1A, 63 bp (ii) exon 1A + 1B, 125 bp or (iii) exon 1C, 101 bp, were expressed in a tissue‐specific manner, we used RT–PCR and exon‐specific oligonucleotide hybridization. Our results suggest two of the variants (1A + 1B and 1A) may utilize the same promoter; however, they are not equally expressed. While in the adult CNS and adrenal medulla, the shorter mRNA consisting of exon 1A was considerably more abundant, in the stomach and heart, the two variants were equally expressed. The third splice variant exon 1C is only expressed in the gut and to a lesser extent in the heart. The data from this study suggest the splice variant consisting of exon 1C may utilize a distinct promoter compared to the other two.