TSIX

Summary

TSIX (TSIX transcript, XIST antisense RNA, HGNC:12377) is a long non-coding RNA gene on chromosome Xq13.2.

In mammals, dosage compensation of genes on the X chromosome occurs by X inactivation, which is regulated in cis by the X-inactivation center (XIC) and expression of the XIST non-coding RNA. This gene expresses a non-coding antisense transcript across the 3’ end of the XIST locus, and is coexpressed with XIST only from the inactive X chromosome. The mouse ortholog of this locus is required for imprinted X inactivation in extraembryonic tissues and silences Xist through modification of the chromatin structure in the Xist promoter region. In contrast, imprinted X inactivation does not occur in human extraembryonic tissues and transcripts from this locus do not repress XIST expression or affect random X chromosome inactivation in embryonic cells. This transcript is thought to be unspliced and extend over more than 30 kb, but its exact nature has not been determined.

Source: NCBI Gene 9383 — RefSeq curated summary.

At a glance

• Gene type: non-coding (lncRNA) — no protein product; not a drug target. Variant/disease associations are omitted (they would be positional, from an overlapping protein-coding gene).

Identifiers

Gene identifiers

Field	Value
HGNC ID	HGNC:12377
Approved symbol	TSIX
Name	TSIX transcript, XIST antisense RNA
Location	Xq13.2
Locus type	RNA, long non-coding
Status	Approved
Aliases	NCRNA00013, XIST-AS1, LINC00013
Ensembl gene	ENSG00000270641
Ensembl biotype	lncRNA
OMIM	300181
Entrez	9383
RNAcentral	URS000025784F — lncRNA, 37027 nt, 1 organism(s)

Gene structure

Transcript identifiers

Ensembl transcripts: 2 — 2 lncRNA

ENST00000604411, ENST00000706914

RefSeq mRNA: 0 — MANE Select: None

Canonical transcript exons

ENST00000604411 — 1 exons

Exon	Start	End
ENSE00003566034	73792205	73829231

Expression profiles

Bgee: expression breadth ubiquitous, 143 present calls, max score 91.79.

Top tissues by expression

186 total, by Bgee expression score (0-100, higher = more expressed):

Tissue	Anatomy ID	Expression score	Quality
oviduct epithelium	UBERON:0004804	91.79	gold quality
buccal mucosa cell	CL:0002336	84.85	silver quality
mammary duct	UBERON:0001765	80.95	gold quality
epithelium of mammary gland	UBERON:0003244	80.78	gold quality
fallopian tube	UBERON:0003889	78.44	gold quality
pericardium	UBERON:0002407	77.61	gold quality
ileal mucosa	UBERON:0000331	76.25	gold quality
Brodmann (1909) area 46	UBERON:0006483	73.65	gold quality
duodenum	UBERON:0002114	70.94	gold quality
male germ line stem cell (sensu Vertebrata) in testis	CL:0000089 ∩ UBERON:0000473	70.54	gold quality
tibialis anterior	UBERON:0001385	66.52	silver quality
kidney epithelium	UBERON:0004819	66.41	gold quality
lower lobe of lung	UBERON:0008949	65.03	silver quality
pancreatic ductal cell	CL:0002079	64.00	silver quality
mucosa of sigmoid colon	UBERON:0004993	63.72	silver quality
small intestine	UBERON:0002108	63.64	gold quality
jejunal mucosa	UBERON:0000399	63.15	gold quality
layer of synovial tissue	UBERON:0007616	62.38	gold quality
pancreas	UBERON:0001264	62.16	silver quality
mammary gland	UBERON:0001911	62.15	gold quality
adipose tissue	UBERON:0001013	62.09	gold quality
skeletal muscle tissue of rectus abdominis	UBERON:0004511	61.74	silver quality
thoracic mammary gland	UBERON:0005200	61.57	gold quality
corpus callosum	UBERON:0002336	60.95	gold quality
endometrium	UBERON:0001295	60.51	gold quality
skin of hip	UBERON:0001554	60.01	gold quality
testis	UBERON:0000473	59.35	silver quality
left ventricle myocardium	UBERON:0006566	59.23	gold quality
jejunum	UBERON:0002115	59.09	gold quality
inferior vagus X ganglion	UBERON:0005363	58.98	gold quality

Single-cell (SCXA)

Detected in 2 experiment(s), a significant marker in 1.

Experiment	Marker?	Max mean expression
E-ANND-3	yes	8.31
E-MTAB-9543	no	1676.42

Regulation

Is transcription factor: no

Upstream regulators (CollecTRI, top): YY1

Literature-anchored findings (GeneRIF, showing 6)

• comparison with mouse counterpart; gene expression (PMID:11555794)
• It’s proposed that Tsix and CTCF together establish a regulatable epigenetic switch for X-inactivation (PMID:11743158)
• Tsix is not required at the onset of random X-inactivation; instead, it protects the active-X from ectopic silencing once X-inactivation has commenced. (PMID:25981039)
• TSIX is overexpressed in systemic sclerosis dermal fibroblasts in vivo and in vitro, and is higher in SSc sera. TSIX is a new regulator of collagen expression and stabilizes its mRNA. TSIX upregulation may result from activated endogenous TGF-beta signaling. (PMID:26566700)
• Authors selected an HCC-specific RNA-based biomarker panel that depended on the integration of suppressor of glucose autophagy-associated (SOGA1) gene expression with the chosen panel of epigenetic regulators of this gene [long non-coding RNA antisense for X-inactive-specific transcript (lncRNA-TSIX) and microRNA-548-a-3p (miR-548-a-3p)]. (PMID:31004302)
• Dysregulation in the expression of (lncRNA-TSIX, TP53INP2 mRNA, miRNA-1283) in spinal cord injury. (PMID:32535070)

Cross-species orthologs

0 orthologs

Protein

Non-coding RNA — no protein product; not a drug target.

Function

No curated pathway, Gene-Ontology, or interaction data.

Disease & clinical

No curated disease, variant, or cancer-driver associations.

Drugs & pharmacology

No drug or pharmacology data — not an established drug target.