What Are Proto-Oncogenes?
Tumors are a type of disease caused by the interaction of environmental factors and genetic factors. The occurrence of tumors is related to genetic changes. Oncogenes and tumor suppressor genes are genes that play important roles in the regulation of cell growth and proliferation. Proto-oncogenes (cell oncogenes) refer to oncogenes that exist in the normal cell genome of a living organism. Under normal circumstances, the proto-oncogenes present in the genome are under-expressed or non-expressed and play important physiological functions. However, under certain conditions, such as viral infection, chemical carcinogens, or radiation effects, proto-oncogenes can be abnormally activated, transformed into oncogenes, and induced cells to become cancerous.
- Chinese name
- Proto-oncogene
- Foreign name
- proto-oncogene
- Nature
- gene
- category
- biology
Basic Information
Proto-oncogene characteristics
- Universality
- Extensive in the biological world.
- 2. Conservative
- During evolution, gene sequences are highly conserved.
- 3. Importance
- Existing in normal cells is not only harmless, but also plays an important role in maintaining normal physiological functions and regulating cell growth and differentiation.
- 4. Harmful
- Under the influence of certain factors, once the proto-oncogene is activated, a quantitative or structural change may cause normal cell canceration.
Proto-oncogene activation mechanism
- The process of transforming from a normal proto-oncogene to an oncogene capable of transforming cells is called proto-oncogene activation. There are four main mechanisms for proto-oncogene activation: obtaining strong promoters and enhancers; chromosomal translocations; gene amplification; and point mutations.
Proto-oncogene classification
- 1.ras family
- The ras gene family is the most common oncogene family, which plays an important role in regulating the proliferation and differentiation of normal cells. It is the most conserved oncogene family currently known.
- 2.myc family
- The myc gene is one of the most widely studied nuclear protein oncogenes, including C-myc, N-myc, L-myc, and R-myc. One of the salient features of the myc gene in malignant tumors is that it is activated by gene amplification and gene mutation, and there are two microchromosomes and homochromic regions of chromosomes. The activated myc gene expresses a large amount of myc protein, which plays an important role in cell growth and differentiation.
- 3.src family
- The product has protein tyrosine kinase activity, can promote the transduction of proliferative signals, and is located on the inner surface of the cell or distributed across the membrane.
- 4.sis family
- The encoded p28 can stimulate cell division and proliferation of mesenchymal tissue.
- 5.myb family
- Nuclear transcription factor.
Proto-oncogene products and functions
- Extracellular growth factor
- Receptors acting on the cell membrane may be passed directly into the cell, activating transcription factors through protein kinases, triggering the transcriptional activation of a series of genes.
- 2. Transmembrane growth factor
- The receptor receives extracellular growth signals and passes them into the cell.
- 3. Intracellular signaling molecules
- The received signal is transmitted from the intracellular to the nucleus to promote cell proliferation.
- 4. Nuclear transcription factor
- Certain oncogene-expressing proteins are localized in the nucleus and, in combination with the cis-regulatory elements of the target gene, directly regulate the transcriptional activity of the target gene.