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T Vasicek

Publications and source records attributed to T Vasicek.

2 recordsLinked to original sources

A translocated human c-myc oncogene is altered in a conserved coding sequence.

We have cloned and characterized a c-myc (now designated MYC) oncogene that had been translocated into the mu switch region of the immunoglobulin heavy chain locus in a Burkitt lymphoma cell line. The breakpoint of the translocation occurs within the first intron of the c-myc gene, thereby separating the untranslocated first exon from the two coding exons. Transcription from the translocated gene arises from a cryptic promoter within the first intron, which produces a 438-nucleotide untranslated 5' region. The amino acid sequence of the protein encoded by the c-myc gene has been substantially altered. In particular, a compensating set of frameshift mutations alters a string of 24 amino acids in a region of the protein tightly conserved in human, mouse, and chicken c-myc genes as well as in the human N-myc and L-myc oncogenes. Despite this, the mutated gene retains a reduced transforming ability in a rat embryo fibroblast focus-formation assay.

Amino Acid Sequence↗

Activation and somatic mutation of the translocated c-myc gene in burkitt lymphoma cells.

In contrast to other human tumors in which the c-myc gene and its transcript are greatly amplified, careful analysis of t(8;14) Burkitt cell lines indicates that the c-myc transcript is marginally, and in some cases not at all, increased by comparison to control lymphoblastoid cell lines. Instead, there is a more subtle alteration in the expression of the translocated c-myc gene characterized by a shift in promoter utilization and an apparent insensitivity to the regulation that inactivates the normal c-myc allele within these same cells. In some Burkitt cell lines, such deregulation might be because of the loss of a putative control region through removal of the large dual promoter/leader segment of the c-myc gene. In other cell lines, however, this deregulation may be explained by somatic mutations that occur within the putative control region even though it is located many hundreds of bases from the translocation breakpoint.

Alleles↗