Identification of urocortin mRNA antisense transcripts in rat tissue

Urocortin (UCN) has 45% sequence homology with corticotropin releasing fact or (CRF) and binds to CRF receptors, We used reverse-transcriptase-polymera se chain reaction to demonstrate the presence of UCN RNA in various brain r egions and in peripheral tissues. Ribonuclease protection assay (RPA) using sense and antisense riboprobes demonstrated the presence of a naturally oc curring antisense UCN RNA transcript in a number of tissues. Northern blot indicated that the antisense transcript was the same size as sense UCN. RPA , using probes that covered bases 1 to 560 of 579 bp sequence of rat UCN, i ndicated that the antisense sequence was complementary to sense UCN but did not contain an open reading frame. Sense and antisense UCN RNA were co-exp ressed in all tissues that contained levels of either transcript detectable by RPA, Sense RNA expression was greater than antisense in the midbrain, t he two transcripts were expressed equally in the hypothalamus and antisense was expressed at higher levels than sense in the liver, heart, and skeleta l muscle. Antisense RNA expression was stress responsive, suggesting that i t may play a role in regulating transcription or translation of UCN mRNA. ( C) 2000 Elsevier Science Inc.