Summary
Glycoprotein CD36, also known as GPIIIb or GPIV, is a major platelet glycoprotein
that bears the newly identified Naka alloantigen. The aim of this study was to clone platelet CD36 and investigate other
forms of CD36-cDNA present in monocytes, endothelial and HEL cells. RNA from above
mentioned cells were reverse transcribed (RT), using specific primers for CD36, and
amplified by the polymerase chain reaction (PCR) technique. Sequencing the different
amplified platelet derived cDNA fragments, spanning the whole coding and flanking
regions, showed the near identity between platelet and CD36-placenta cDNA. Platelet
CD36-cDNA cross-hybridized, in Southern blots, with RT-PCR amplified cDNA originating
from monocytes, endothelial and HEL cells. However, monocytes showed a RT-PCR amplified
cDNA fragment (561 bp) that was present in platelets and placenta but not on endothelial
on HEL-cells. Northern blot analysis of platelet RNA hybridized with placenta CD36
indicated the presence of a major (1.95 kb) and a minor (0.95 kb) transcript. The
1.95 kb transcript was the only one observed on Northern blots of monocytes, endothelial
and HEL cells. These results indicate that the structure of CD36 expressed in platelets
is similar, with the exception of the 3’ flanking region, to that of placenta. Differences
in apparent molecular weight between CD36 and CD36-like glycoproteins may be due to
post-translational modifications.
