Physiological stresses increase mouse short interspersed element (SINE) RNA expression in vivo

The possible functionality of short interspersed elements (SINEs) is invest igated by assaying the effects of physiological stress on their RNA polymer ase-III-directed transcriptional expression in vivo. B2 RNA is expressed at moderately high levels in all mouse tissues investigated, namely liver, sp leen, kidney and testis. III RNA is expressed in testis but is nearly undet ectable in the other tissues. Following hyperthermic shock, the amounts of B1 and B2 SINE RNAs transiently increase in all tissues by as much as 40-fo ld in certain cases. The kinetics of these increases resemble those of heat shock protein mRNAs. An acute dose of ethanol also transiently increases t he abundance of B1 and B2 RNA in liver, showing that other physiological st resses increase SINE RNA expression. The constitutive expression of B2 RNA in all tissues and tissue-specific differences in expression of B1 RNA impl y that these transcripts serve a normal physiological function(s). Moreover , increased SINE RNA expression is a vital response to stress and by the cr iterion of their inducibility, mammalian SINEs behave like regulated cell s tress genes. (C) 1999 Elsevier Science B.V. All rights reserved.