Gene analysis of platelet-Naka antigen expression on monocytes in platelet-Naka- subjects.

We have already demonstrated that Naka antigen (GPIV) is expressed on the monocytes in platelet-Naka- subjects. To define the molecular basis for the discrepancies of GPIV expression between monocytes and platelets in Naka- subjects, we studied whether there are differences in monocyte GPIV mRNA obtained from Naka- and Naka+ subjects, and compared these monocyte GPIV mRNA with Naka- platelet GPIV mRNA which we have recently reported.In Northern blot analysis, monocyte GPIV mRNA from two platelet-Naka- subjects exhibited the same size of 2.9kb and nearly the same amounts as that from platelet-Naka+ subject. And restriction enzyme analysis of GPIV cDNAs which were amplified by a reverse transcription polymerase chain reaction (RT-PCR) showed predictable fragment length.We have already shown that RT-PCR analysis of GPIV mRNA from both Naka- and Naka+ platelets and restriction enzyme analysis of these PCR products show no apparent differences between them. Thus, we conclude that GPIV mRNA from both monocytes and platelets in Naka- subjects has no apparent abnormalities and seems to be the same as that in Naka+ subjects.