Introns determine the time of appearance of PCNA mRNA in 3T3 cells stimulated by growth factors.
In quiescent fibroblasts stimulated to proliferate, the mRNAs for several DNA synthesis genes increase sharply at the G1/S boundary. However, the corresponding hnRNAs often increase shortly after stimulation, several hours before the increase in mRNA levels. To investigate the delay that occurs between the increases in hnRNA and mRNA levels, we have used several constructs of the human PCNA gene stably transfected into Balb/c-3T3 cells. The 3' untranslated region of the PCNA gene can be replaced without affecting the time course of appearance of the mature RNA. However, when the introns are deleted, the mRNA levels are already high in quiescent cells and increase as cells progress through G1. These experiments define the introns of the human PCNA gene as responsible for the delay in the appearance of the PCNA mRNA that occurs in stimulated Balb/c-3T3 cells.
Charollais
R H
RH
Department of Microbiology and Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107.
Surmacz
E
E
Baserga
R
R
D016475:3T3 Cells; D000818:Animals; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D001483:Base Sequence; D017931:DNA Primers; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D007438:Introns; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D000951:Antigens, Neoplasm; D017931:DNA Primers; D006133:Growth Substances; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger