FATTY-ACIDS REGULATE THY-1 ANTIGEN MESSENGER-RNA STABILITY IN T-LYMPHOCYTE PRECURSORS

In this study, we report the effect of fatty acids on the Thy-1 antige n mRNA decay. Low serum and synthetic medium culture conditions were u sed to demonstrate that fatty acids, which are important metabolites i nvolved as second messengers in signal transduction, also influence th e steady-state mRNA level. Detailed analysis demonstrated that polyuns aturated lipids attached to bovine serum albumin, such as linoleic, li nolenic, and arachidonic acids, modulate gene expression specifically in the S1A T lymphoma cell line by inducing a 3-5-fold increase in the steady-state Thy-1 mRNA level, concomitant with a twofold increase in cell surface expression. A similar modulation was observed in the imm ature CD4(-)CD8(-) T cell precursors but not in mature thymocytes. Nuc lear run-on and transfection experiments indicated that the observed T hy-1 mRNA level is post-transcriptionally regulated and that the prese nce of the coding region is sufficient for this adaptive response. A m echanism without a requirement for protein kinase C activation, but in volving Ca2+ entry, could account for this difference in Thy-1 mRNA st ability.