Genomic organization and tissue-specific expression of rat urocortin

The genomic organization of rat urocortin was determined using both cDNA an d liver genomic DNA as templates for polymerase chain reactions. A single i ntron of 261 bp was found upstream to the ATG start codon, and the whole ur ocortin coding sequence was shown to be contained in a single exon. Relying on these results, oligonucleotide primers were designed, which can differe ntiate genomic DNA contamination from cDNA-derived signals in a reverse tra nscription-polymerase chain reaction. Tissue screening for urocortin expres sion revealed that the mid-brain is the major site of urocortin mRNA expres sion, and that other peripheral organs, including lymphoid tissues and peri pheral blood lymphocytes, do not produce urocortin. (C) 2000 Elsevier Scien ce Ireland Ltd. All rights reserved.