Putative repressor binding sites in the regions mediating transcriptional control of viral and cellular genes

A model to account for the effects of oncogenes, TPA, and retinoic acid on the regulation of genes involved in metastasis

We have postulated that signals from the microenvironment can induce shifts in tumor cell phenotypes and that microenvironmental factors are therefore important for cancer metastasis. In this article we expand on this hypothesis and propose a model to explain (a) how extracellular signals can lead to changes in tumor phenotypes, and (b) how cytoplasmic oncogenes, which influence signal transducing pathways as well as nuclear oncogenes regulating gene expression via DNA binding transacting factors, might affect metastatic competence.

Conserved 12-bp element downstream from mRNA polyadenylation sites

Sequences downstream from the AATAAA motif in a number of cellular and viral transcription units have been compared. A 12-bp conserved element was identified in approximately half of the cases studied, and a consensus sequence TTGANNNTTTTTT was derived from a comparison of 74 such sequences. This element is located immediately (5-20 bp) downstream from the poly(A)-addition site in every case where this is known, and it is suggested that this element may be involved in the cleavage/polyadenylation reaction. This proposal is consistent with published studies on deletion mutants of downstream regions.

Conserved elements in the 3' untranslated regions of c-fos and actin mRNAs

In this study, the nucleotide sequences of the 3' untranslated regions (UTR) of the mouse and human c-fos genes, and the rat and human beta-actin genes were examined. It is shown (i) that the 3' UTR of c-fos is highly conserved between mouse and man, (ii) that multiple copies of a 12 bp element occur, in clusters, in the 3' UTR both of c-fos and of beta-actin. This conserved 12 bp element is analogous to the putative repressor binding site previously identified (Renan, Bioscience Reports, 5 (1985), 739-753). These findings provide additional support for the proposal that regulatory signals are located in the 3' UTR's of certain genes.