[Detection of p27/kip1 mRNA in blood cells by nonradioactive ribonuclease protection assay].

Cyclin and cyclin-dependent kinase(cdk) complexes, and their inhibitors (CKIs) play important roles in growth regulation on the cells. p27/kip1 is a CKI associated with G1 arrest induced by cell to cell contact, transforming growth factor-beta and cyclic AMP. The abnormality of p27/Kip1 genes in human tumors usually appears as a steady level defect of expression, since mutations in them is rare. Thus it is important to estimate the expression level of this gene. To detect the change of p27/Kip1 mRNA level in blood cells, we developed the ribonuclease protection assay using nonradioactive riboprobe which was produced by reverse transcriptase-polymerase chain reaction (RT-PCR) with T7 promoter-added antisense primer and the in vitro transcription system. Our assay may be useful for clinical evaluation of the mRNA level.