Difference between revisions of "XACT"

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===Evolution===
 
===Evolution===
Although the organization of the genomic region encompassing AMOT and HTR2C is well conserved in placental mammals and marsupials, the sequence between these two genes shows moderate conservation, with several conserved blocks present in placental mammals but not marsupials. The LTR that corresponds to the 5' end of XACT is conserved in chimpanzees but not macaques or more distally related species, suggesting that the insertion of these LTR elements is a very recent event <ref name="ref1" />.
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Although the organization of the genomic region encompassing AMOT and HTR2C is well conserved in placental mammals and marsupials, the sequence between these two genes shows moderate conservation, with several conserved blocks present in placental mammals but not marsupials. The LTR (long terminal repeat) that corresponds to the 5' end of XACT is conserved in chimpanzees but not macaques or more distally related species, suggesting that the insertion of these LTR elements is a very recent event <ref name="ref1" />.
  
No XACT-like transcript expression is detected in mouse, which indicates that XACT might not be conserved in mice <ref name="ref1" />.
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No XACT-like transcript expression is detected in mouse, which indicates that XACT might not be conserved in mouse <ref name="ref1" />.
  
 
===Expression===
 
===Expression===

Revision as of 08:20, 26 September 2017

Annotated Information

Approved Symbol

XACT: X active specific transcript

Chromosome

Xq23

RefSeq ID

NR_131204

OMIM ID

300901

Ensembl ID

ENSG00000241743

Characteristics

XACT is a 251.8-kb transcription unit(112,983,323–113,235,148 bp) and it is located on chromosome Xq23 between the protein-coding genes AMOT and HTR2C [1]. XACT is polyadenylated and belongs to intergenic lncRNA group [1].

Cellular Location

XACT is mostly nuclear [1].

Function

XACT is involved in the control of XCI (X-chromosome inactivation) initiation in human [1]. XACT is expressed from and coats the active X chromosome specifically in human pluripotent cells. In the absence of XIST, XACT is expressed from both X chromosomes in human but not in mouse, suggesting a unique role for XACT in the control of human XCI initiation [1].

(a)Localization of XACT and XIST on the human X chromosome (b)RT-PCR analysis (c,d,e)FISH analysis (f) Three-dimensional model of the nuclear volumes occupied by XACT and XIST RNAs.[1]

Evolution

Although the organization of the genomic region encompassing AMOT and HTR2C is well conserved in placental mammals and marsupials, the sequence between these two genes shows moderate conservation, with several conserved blocks present in placental mammals but not marsupials. The LTR (long terminal repeat) that corresponds to the 5' end of XACT is conserved in chimpanzees but not macaques or more distally related species, suggesting that the insertion of these LTR elements is a very recent event [1].

No XACT-like transcript expression is detected in mouse, which indicates that XACT might not be conserved in mouse [1].

Expression

XACT is expressed in active X chromosome in human but not in mouse, and the expression of XACT is restricted to pluripotent and early differentiating cells in human [1].

Sequence

>gi|784642207|ref|NR_131204.1| Homo sapiens X active specific transcript (non-protein coding) (XACT), long non-coding RNA

000001 TTTGTGGATG AGTCAATGAA GAAACTTGTC AAAGCACTTC AATTAAAACA CAGAAACTAT AGAAAATCAT CTGGTAAACA 000080
000081 TGCTGATGAT GTCCTAAACC TGATCACTTG TCTCAAAATT TAGAAAGTTA ATGGCTGAAG ATTCAGCAGC CATTCTGAAC 000160
000161 TGGAAATTAC ATGTTAAGGC TGTTATAGAA GAAATAAAGA AATTAAATCT CTATGTCCCC AAGGTATCTC TATACCGGCC 000240
000241 TGGAATGCCT ATCTCCAAAC CTCCTTTACA TGAGACAGAA ACAGCTTCTA TCACCTTAAA ATCTGTTACT TTAGGTTTTT 000320
000321 TTCATTATGA GCAGCTAAAA TGAATCTTAC TTGATACAGT GTGAGTGTTC ATGGATTAGG GCATTGTTTG ATAAGAGGAG 000400
000401 TAAGAAAAGA ATATAAATTG TATTGGCCCT GATATGCCAC AAACAATGAG GGCTGAAGCC AAATTAATCA AAGAATAAAC 000480
000481 TCAAATACAA AGAACAAAAA AAAAAAAAA

Labs working on this lncRNA

  • University Paris Diderot, Sorbonne Paris City, Epigenetics and Cell Fate, Paris, France [1].

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Vallot, C., et al., XACT, a long noncoding transcript coating the active X chromosome in human pluripotent cells. Nat Genet, 2013. 45(3): p. 239-41.