random inactivation of X chromosome
Definition
Target type: biologicalprocess
Compensating for the two-fold variation in X-chromosome:autosome ratios between sexes by a global inactivation of all, or most of, the genes on either the paternal or maternal X-chromosome in the XX sex. [GOC:dph, GOC:sdb_2009, GOC:tb, PMID:32189388]
Random inactivation of the X chromosome, also known as X-inactivation, is a process that occurs in female mammals to compensate for the dosage difference between males (XY) and females (XX) in terms of X-linked genes. This intricate mechanism ensures that females do not express twice the amount of X-linked gene products compared to males.
The process begins early in embryonic development, typically around the 16-cell stage. One of the two X chromosomes in each cell is randomly chosen to be inactivated, becoming highly condensed and forming a structure called a Barr body. This inactive X chromosome is largely silenced, meaning its genes are not transcribed into RNA.
The selection of which X chromosome to inactivate is random and independent in each cell. This means that different cells in a female’s body can have different X chromosomes inactivated, leading to a mosaic pattern of X chromosome expression.
The inactivation process is initiated by a non-coding RNA called XIST (X-inactive specific transcript). XIST is transcribed from the X chromosome that will be inactivated and coats that chromosome, silencing its genes.
The X chromosome inactivation process is a complex and tightly regulated process involving several key factors. It is essential for proper development in female mammals and helps to ensure equal expression of X-linked genes between males and females.
X inactivation has important implications for human health. It explains why females who carry a mutated X chromosome may not exhibit the same severity of disease as males with the same mutation. However, the random nature of X inactivation can also lead to variations in disease expression among females, depending on which X chromosome is inactivated in different cells.'
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Proteins (2)
| Protein | Definition | Taxonomy |
|---|---|---|
| Polycomb protein SUZ12 | A polycomb protein SUZ12 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q15022] | Homo sapiens (human) |
| Breast cancer type 1 susceptibility protein | A breast cancer type 1 susceptibility protein that is encoded in the genome of human. [PRO:DNx] | Homo sapiens (human) |
Compounds (7)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| beta-thujaplicin | beta-thujaplicin : A monoterpenoid that is cyclohepta-2,4,6-trien-1-one substituted by a hydroxy group at position 2 and an isopropyl group at position 4. Isolated from Thuja plicata and Chamaecyparis obtusa, it exhibits antimicrobial activities. beta-thujaplicin: structure | cyclic ketone; enol; monoterpenoid | antibacterial agent; antifungal agent; antineoplastic agent; antiplasmodial drug; plant metabolite |
| tanshinone | tanshinone: from root of Salvia miltiorrhiza Bunge; RN given refers to tanshinone I; cardioprotective agent and neuroprotective agent | abietane diterpenoid | anticoronaviral agent |
| przewaquinone d | przewaquinone D: isolated from root of Salvia przewalskii; structure given in first source; RN given refers to the trans- isomer, przewaquinone D | ||
| tanshinone ii a | tashinone IIA: a cardiovascular agent with antineoplastic activity; isolated from Salvia miltiorrhiza; structure in first source | abietane diterpenoid | |
| epz-6438 | tazemetostat: a histone methyltransferase EZH2 inhibitor with antineoplastic activity | ||
| gsk-2816126 | GSK-2816126: inhibits EZH2 methyltransferase; structure in first source | piperazines; pyridines | |
| gsk343 | GSK343 : A member of the class of indazoles that is 1-isopropyl-1H-indazole-4-carboxamide in which the nitrogen of the carboxamide group is substituted by a (6-methyl-2-oxo-4-propyl-1,2-dihydropyridin-3-yl)methyl group and in which the indazole ring is substituted at position 6 by a 2-(4-methylpiperazin-1-yl)pyridin-4-yl group. A highly potent and selective EZH2 inhibitor (IC50 = 4 nM). GSK343: an EZH2 methyltransferase inhibitor | aminopyridine; indazoles; N-alkylpiperazine; N-arylpiperazine; pyridone; secondary carboxamide | antineoplastic agent; apoptosis inducer; EC 2.1.1.43 (enhancer of zeste homolog 2) inhibitor |