Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0684249 (lung carcinoma)
 23,830 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oncogenic activation of myc genes in human cancer involves deregulated expression of myc proteins with no major structural alterations. Here two independent small cell lung carcinoma (SCLC) cell lines were found to express similar novel proteins antigenically related to L-myc. cDNAs corresponding to these proteins were cloned and shown to encode chimeric polypeptides with amino-terminal sequences from a novel gene named rlf joined to the L-myc protein. Although the chimeric mRNAs were shown to be identical, they result from distinct DNA rearrangements. The L-myc fusion protein may represent another activation mechanism of the myc proto-oncogenes.
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PMID:A fusion protein formed by L-myc and a novel gene in SCLC. 185 Oct 85

The L-myc gene is the third member of the myc family of proto-oncogenes. Amplification and elevated expression of the L-myc gene has been detected in a subset of small cell lung carcinoma (SCLC) cell lines. The biological properties and functions of the L-myc gene and its product have not yet been elucidated. Monoclonal antibodies against two myc homology boxes were used to characterize the L-myc gene product. These antibodies react with two groups of polypeptides of apparent masses of 60, 61 and 66 kd (the long forms), and 34 and 37 kd (the short forms) in SCLC cells expressing L-myc transcripts. The long form L-myc proteins are associated with the nuclear fraction of the cells. The short form L-myc proteins are present in the cytoplasmic fraction, though diffusion of the short forms from the nucleus during cell fractionation cannot be ruled out. The half-life of the long form polypeptides is approximately 45-90 min. The short form polypeptides have a half-life of approximately 120-180 min. The L-myc protein is not detectable in the mitotic cells, suggesting that the L-myc protein expression is tightly regulated during the cell cycle.
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PMID:The human L-myc gene is expressed as two forms of protein in small cell lung carcinoma cell lines: detection by monoclonal antibodies specific to two myc homology box sequences. 254 55

We have determined the nucleotide sequence and transforming activity of the human L-myc gene and a processed L-myc pseudogene (L-myc psi). We demonstrate by cotransformation assays that a 10.6-kb EcoRI fragment derived from a human placental library contains a complete and functional L-myc gene including transcriptional regulatory sequences sufficient for expression in rat embryo fibroblasts. Organization of the L-myc gene was determined by comparing its sequence to those of the L-myc psi gene and an L-myc cDNA clone derived from a human small cell lung carcinoma. Our results show that L-myc has a three-exon organization similar to that of the c-myc and N-myc genes. The putative L-myc gene product consists of 364 amino acids and contains five of the seven homology regions highly conserved between c-myc and N-myc. These conserved regions are located along the entire length of the putative L-myc protein and are interspersed among nonconserved regions. While the putative L-myc gene product is of a smaller size when compared to the c- and N-myc proteins, the relative positions of certain conserved residues occur in corresponding locations along the peptide backbone of the three proteins. In addition, comparison of the human and murine L-myc gene sequences indicate that the relatively large 5' and 3' untranslated regions are evolutionarily conserved, but that these sequences are totally divergent between the L-, c-, and N-myc genes. Finally, we demonstrate that, like the N- and c-myc genes, the L-myc gene can cooperate with a mutant Ha-ras gene to cause malignant transformation of rat embryo fibroblasts in culture. Our analyses clearly prove that L-myc represents a functional member of the myc oncogene family and further delineate structural features that may be important for the common and divergent functions of the members of this gene family.
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PMID:The human myc gene family: structure and activity of L-myc and an L-myc pseudogene. 332 39