KIDNEY EXTRACTS FROM SPONTANEOUSLY HYPERTENSIVE RATS (SBR) HAVE GREATER DOPAMINE 1A RECEPTOR RNA-BINDING ACTIVITY THAN EXTRACTS FROM NORMOTENSIVE WISTAR-KYOTO (WKY) RATS

Rat kidney extracts contain a 52 kDa protein that binds to the 3' untr anslated region of the dopamine 1A (D1A) receptor mRNA at a 243 base-l ong cis element starting at the stop codon and ending similar to 220 b ases upstream of an AUUUA-rich region. The DIA receptor RNA-binding pr otein (D1A-BP) is redox-sensitive; free sulfhydryl groups on the prote in are required for binding. Kidney extracts from SHR have significant ly more D1A-BP activity than extracts from WKY rats. When kidney extra cts were tested for binding to an 80-base RNA containing four AUUUA re peats, there was also greater binding activity in extracts from SHR. T hese increases are at least partly specific because there was no diffe rence in catalase RNA-binding protein activity between the two rat str ains. These data suggest DIA-BP and AUUUA-binding protein may play a r ole in posttranscriptional regulation of the D1A receptor in the hyper tensive rat.