Table 1.
The known biological activities of Gag-like proteins.
| Gag-like genea | Species | Tissue expressionb | Biological activities | Virus-like properties | References |
|---|---|---|---|---|---|
| Arc | Mammals and some insects | Brain, testes, and dendritic cells | Regulates endocytosis at synapses to tune synaptic strength. Essential for long-term memory. | Forms virus-like particles and transfers RNA between cells. | [4, 5, 18] |
| PNMA4/MOAP1 | Mammals | Ubiquitous | Promotes apoptosis | Unknown | [91] |
| RTL1/Peg11 | Eutherian mammals | Adrenal gland, brain, and placenta | Essential to maintain placental capillaries. | Unknown | [92] |
| RTL2/Peg10 | Eutherian mammals | Placenta, adrenal gland, pituitary gland, and brain | Promotes cell proliferation, inhibits apoptosis, and blocks TGF-beta signaling. Contributes to tumorigenesis. | Transfers RNA between cells, unknown if can form capsids. | [70, 93, 94] |
| RTL3/Sirh9 | Eutherian mammals | Ubiquitous | Controls collagen release through transcriptional regulation. | Unknown | [95] |
| RTL4/Sirh11 | Eutherian mammals | Brain, testes, ovaries, kidneys, and liver | Regulates noradrenaline levels and influences spatial working memory. | Unknown | [69] |
| RTL7/Sirh7/Ldoc1 | Eutherian mammals | Ubiquitous | Controls placental development and suppresses immune signaling. | Unknown | [96, 97] |
a
As determined by sequence homology
b
As found in the Human Protein Atlas (https://www.proteinatlas.org/)