Half-lives of different sized mRNAs for the PKA subunit RI alpha are regulated differently in response to inhibition of transcription and translation.

ABSTRACT

The RI alpha mRNA level is induced 3-5 times by FSH or cAMP analogs in primary cultures of rat Sertoli cells. In rat tissues, the RI alpha gene gives rise to three different mRNAs of different size 3.2, 2.9 and 1.7 kb. In the present study we report that the 1.7 kb transcript has a shorter half-life than the two other mRNAs. In cells which had been pre-stimulated with a cAMP analog, inhibition of transcription stabilizes the two larger, but not the smaller sized RI alpha mRNA. However, in contrast, inhibition of protein synthesis stabilizes all the RI alpha mRNAs. Thus, degradation of various mRNAs coding for the same protein reveals different dependencies on transcription and translation.