~300 nucleotide, nonpolyadenylated, RNAP III transcript. SINE (short interspersed nucleotide element - AluJb). 21A lacks the Alu-specific intragenic consensus elements needed to promote its pol III transcription such as the blocks A and B, which points to transcription driven by an extragenic type 3 pol III promoter.
Very low free energy (deltaG) value (deltaG < -100) indicating strong secondary structure.
Nuclear localisation. Detected in tested cultured cells such as HeLa and skin fibroblast cells.
The level of 21A transcription was very low in three immortalized, fully proliferating cell lines (HeLa, 293T, and LAN5) compared to unproliferating/resting PBL (peripheral blood lymphocyte) cells. Similarly, the 21A RNA level in primary skin fibroblasts was higher than in 293T cells, reinforcing an inverse correlation between endogenous 21A expression and cell proliferation.
Please input regulation information here.
- 21A is one of a number of RNAP III-transcribed short ncRNAs that have sequence complementarity to protein-coding genes, possibly acting as as a natural trans-chromosomal antisense RNA. Aligned to the human genome, it shows several homology hits, among which the most highly significant were associated to multiple intronic regions of centromeric protein F gene (CENP-F). In vitro over-expression of 21AS transcripts inhibits CENP-F protein accumulation and decreased levels of CENP-F mRNA, indicating that 21AS regulates CENP-F expression in trans.
- 21A RNAs has a role in the control of the proliferation of human tumor cell lines, possibly via regulation of CENP-F expression. This effect was not observed in a mouse cell line.
Please input disease information here.
Please input evolution information here.
Labs working on this lncRNA
- Dipartimento di Oncologia Biologia e Genetica, Università di Genova, Genoa, Italy 
- Pagano A, Castelnuovo M, Tortelli F, Ferrari R, Dieci G, Cancedda R. New small nuclear RNA gene-like transcriptional units as sources of regulatory transcripts. PLoS Genet. 2007 Feb 2;3(2):e1. Epub 2006 Nov 20.