Substitution of just five nucleotides at and around the transcription start site of rat beta-actin promoter is sufficient to render the resulting transcript a subject for translational control

FEBS Lett. 1997 Apr 1;405(3):333-6. doi: 10.1016/s0014-5793(97)00234-2.


Vertebrate mRNAs with a 5' terminal oligopyrimidine tract (5' TOP), including those encoding ribosomal proteins and elongation factors, are candidates for translational control in a growth-dependent fashion. The present study was designed to determine the minimal cis-regulatory element involved in this mode of regulation. We selected rat beta-actin mRNA, a typical translationally uncontrolled transcript, as a subject for gain-of-function analysis. Mutations at and around its cap site leading to the formation of a 7 pyrimidines long 5' TOP render the resulting transcript translationally repressed upon growth arrest of lymphosarcoma cells. In contrast, growth-dependent translational control of this mRNA in fibroblasts requires, in addition, a GC motif downstream of the 5' TOP. A similar motif is present in all ribosomal prtein mRNAs shown to be translationally controlled.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 3T3 Cells
  • Actins / genetics*
  • Animals
  • Base Composition
  • Gene Expression Regulation
  • Human Growth Hormone / genetics
  • Mice
  • Promoter Regions, Genetic*
  • Protein Biosynthesis*
  • Rats
  • Structure-Activity Relationship


  • Actins
  • Human Growth Hormone