gene Related Biological Terms

A gene present in normal cells which when altered can transform the normal cell into a malignant cell. (When emphasizing this relationship, the unaltered gene is called a proto-oncogene and the altered gene, an oncogene.) The alteration may result in overproduction of a gene product or faulty function. An oncogene is denoted by the prefix c if a cellular oncogene, e.g. c-ras, or by the prefix v if a viral oncogene, e.g. v-ras, which is presumed to have originated from a capture of the c-oncogene by the virus during an infection of a normal cell. Contrasted with a thanatogene, or death gene, which when activated leads to apoptosis. (see also anti-oncogene (tumour suppressor gene); oncoprotein)Marx, J. (1994) Science 266, 1942-1944

The proposal that arose from genetic studies on the effects on amino acid metabolism of mutations in Neurospora, that there is a one-to-one correspondence between enzymes and the genes that encode them.

A rare phenomenon found in small viral genomes whereby a single mRNA can be translated in two different reading frames to produce two different proteins.

A reconstruction of the evolutionary relationship of contemporary species that shows their divergence from common ancestors and the branch points at which different species separated. A common ancestor is presented at the base of a central stem, and the tree ramifies as it ascends, often with distance from the base roughly related to evolutionary time. The relationships it displays are usually inferred from the similarities of amino acid sequences of contemporary proteins or of the base sequences of contemporary nucleic acids.

A procedure for creating a genome-wide library of cDNAs by use of several insertion vectors, each containing a promoter sequence linked to an exon and followed by an unpaired splice site. transfection into eukaryotic cells allows the vectors to randomly insert by non-homologous recombination. Where the insertion is upstream from a host cell gene, it activates expression of a transcript that encodes a chimeric protein that containing the vector-encoded sequence and some or all of the host cell protein.Harrington, J.J., Sherf, B., Rundlett, S. et al. (2001) Nat. Biotechnol. 19, 440-445

(= saturation mutagenesis (random oligonucleotide mutagenesis))

An oncogene of the murine sarcoma virus. (see also ras protein)

A method for detection of a specific mutation that does not itself cause a unique restriction fragment length polymorphism, because it neither creates nor removes a known restriction site. A new restriction site is created by the introduction of a deliberately mismatched PCR primer, the 5'-end of which is designed to hybridize to the mutant template and the 3'-end of which encodes a new restriction site. (see also mismatched PCR)Ehrlich, G., Ginzberg, D., Loewenstein, Y., et al. (1994) genomics 22, 288-295

(= positional cloning (reverse genetics))

A technique to mutate all bases of a gene. DNA synthesis proceeds from an assortment of oligonucleotide primers synthesized by substitution at each point of the sequence of all three incorrect nucleotides, so that an unbiased assortment of mutants is generated for the span of DNA covered by the primer. Use of other modified primers to cover the length of the gene produces a complete library of mutants.