| genes, gag | DNA sequences that form the coding region for proteins associated with the viral core in retroviruses. Gag is short for group-specific antigen. (12 Dec 1998) |
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| genes, helminth | The hereditary material of helminths. (12 Dec 1998) |
| genes, homeobox | Highly conserved DNA sequences which have been identified in specific gene transcripts ranging from those of drosophila melanogaster to mouse and human. Homeobox genes function, in part, to generate DNA-binding proteins with an evolutionary conserved approximately 60-residue sequence (homeodomain proteins). (12 Dec 1998) |
| genes, immediate-early | Genes that show rapid and transient expression in the absence of de novo protein synthesis. The term was originally used exclusively for viral genes where immediate-early referred to transcription immediately following virus integration into the host cell. It is also used to describe cellular genes which are expressed immediately after resting cells are stimulated by extracellular signals such as growth factors and neurotransmitters. (12 Dec 1998) |
| genes, immunoglobulin | Genes encoding the light and heavy chain segments of immunoglobulins. Light chain gene segments are symbolised l-v (variable), j (joining) and c (constant); ig heavy chain segments have, in addition, a diversity (d) gene. Each segment codes for certain amino acids, and each has a different nucleotide sequence; the genes are assembled by a remarkable shuffling of the segments during b lymphocyte maturation. (12 Dec 1998) |
| genes, insect | The hereditary material of insects. (12 Dec 1998) |
| genes, intracisternal a-particle | A family of retrovirus-like genetic elements coding for virus-like particles found regularly in early rodent embryos (2-cell to blastocyst stage), but which, under certain circumstances such as DNA hypomethylation, are transcribed in a wide variety of neoplasms, including plasmacytomas, neuroblastomas, rhabdomyosarcomas, teratocarcinomas, and colon carcinomas. (12 Dec 1998) |
| genes, jun | Retrovirus-associated DNA sequences (jun) originally isolated from the avian sarcoma virus 17 (asv 17). The proto-oncogene jun (c-jun) codes for a nuclear protein which is involved in growth-related transcriptional control. Insertion of c-jun into asv-17 or the constitutive expression of the c-jun protein produces tumourgenicity. The human c-jun gene is located at 1p31-32 on the short arm of chromosome 1. (12 Dec 1998) |
| genes, lethal | Genes which result in the premature death of the organism; dominant lethal genes kill heterozygotes, whereas recessive lethal genes kill only homozygotes. (12 Dec 1998) |
| genes, mcc | Tumour suppressor genes located in the 5q21 region on the long arm of human chromosome 5. The mutation of these genes is associated with the formation of colourectal cancer (mcc stands for mutated in colourectal cancer). (12 Dec 1998) |
| genes, mdr | Genes responsible for multidrug resistance resulting from their overexpression in mammalian cells. Mammalian p-glycoproteins are encoded by small mdr gene familes. The human multidrug resistance 1 (mdr1) gene responds to environmental stress including various anticancer agents. It is a major determinant in the development of resistance to a large number of cancer chemotherapeutic agents. (biochem biophys res commun 1994;199(3):1428-35; cancer res 1994:54(6):1536-41) (12 Dec 1998) |
| genes, MHC class I | Genetic loci in the vertebrate major histocompatibility complex which encode polymorphic characteristics not related to immune responsiveness or complement activity, e.g., b loci (chicken), dla (dog), gpla (guinea pig), h-2 (mouse), rt-1 (rat), HLA-a, -b, and -c class I genes of man. (12 Dec 1998) |
| genes, MHC class II | Genetic loci in the vertebrate major histocompatibility complex that encode polymorphic products which control the immune response to specific antigens. The genes are found in the HLA-d region in humans and in the I region in mice. (12 Dec 1998) |
| genes, mos | Retrovirus-associated DNA sequences (mos) originally isolated from the moloney murine sarcoma virus (mo-msv). The proto-oncogene mos (c-mos) codes for a protein which is a member of the serine kinase family. There is no evidence as yet that human c-mos can become transformed or has a role in human cancer. However, in mice, activation can occur when the retrovirus-like intracisternal a-particle inserts itself near the c-mos sequence. The human c-mos gene is located at 8q22 on the long arm of chromosome 8. (12 Dec 1998) |
| genes, myc | Family of retrovirus-associated DNA sequences (myc) originally isolated from an avian myelocytomatosis virus. The proto-oncogene myc (c-myc) codes for a nuclear protein which is involved in nucleic acid metabolism and in mediating the cellular response to growth factors. Truncation of the first exon, which appears to regulate c-myc expression, is crucial for tumourigenicity. The human c-myc gene is located at 8q24 on the long arm of chromosome 8. (12 Dec 1998) |