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Antisense RNA (asRNA), also referred to as antisense transcript, natural antisense transcript (NAT) or antisense oligonucleotide, is a single stranded RNA that is complementary to a protein coding messenger RNA (mRNA) with which it hybridizes, and thereby blocks its translation into protein. The asRNAs have been found in both prokaryotes and eukaryotes, and can be classified into short and long non-coding RNAs (ncRNAs). The primary function of asRNA is regulating gene expression. asRNAs may also be produced synthetically and have found wide spread use as research tools for gene knockdown. They may also have therapeutic applications.
This is a list of topics in molecular biology. See also index of biochemistry articles.
Genetics, a discipline of biology, is the science of heredity and variation in living organisms.
fChromosome 9 is one of the 23 pairs of chromosomes in humans. Humans normally have two copies of this chromosome, as they normally do with all chromosomes. Chromosome 9 spans about 150 million base pairs of nucleic acids and represents between 4.0 and 4.5% of the total DNA in cells.
In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context, sense may have slightly different meanings. For example, negative-sense strand of DNA is equivalent to the template strand, whereas the positive-sense strand is the non-template strand whose nucleotide sequence is equivalent to the sequence of the mRNA transcript.
Suppressor of tumorigenicity protein 7 is a protein that in humans is encoded by the ST7 gene. ST7 orthologs have been identified in all mammals for which complete genome data are available.
KCNQ1 overlapping transcript 1, also known as KCNQ1OT1, is a long non-coding RNA gene found in the KCNQ1 locus. This locus consists of 8–10 protein-coding genes, specifically expressed from the maternal allele, and the paternally expressed non-coding RNA gene KCNQ1OT1. KCNQ1OT1 and KCNQ1 are imprinted genes and are part of an imprinting control region (ICR). Mitsuya identified that KCNQ1OT1 is an antisense transcript of KCNQ1. KCNQ1OT1 is a paternally expressed allele and KCNQ1 is a maternally expressed allele. KCNQ1OT1 is a nuclear, 91 kb transcript, found in close proximity to the nucleolus in certain cell types.
Deleted in lymphocytic leukemia 2 is a long non-coding RNA that in humans is encoded by the DLEU2 gene. In humans it is located on chromosome 13q14. The DLEU2 gene was originally identified as a potential tumour suppressor gene and is often deleted in patients with B-cell chronic lymphocytic leukemia.
Natural antisense transcripts (NATs) are a group of RNAs encoded within a cell that have transcript complementarity to other RNA transcripts. They have been identified in multiple eukaryotes, including humans, mice, yeast and Arabidopsis thaliana. This class of RNAs includes both protein-coding and non-coding RNAs. Current evidence has suggested a variety of regulatory roles for NATs, such as RNA interference (RNAi), alternative splicing, genomic imprinting, and X-chromosome inactivation. NATs are broadly grouped into two categories based on whether they act in cis or in trans. Trans-NATs are transcribed from a different location than their targets and usually have complementarity to multiple transcripts with some mismatches. MicroRNAs (miRNA) are an example of trans-NATs that can target multiple transcripts with a few mismatches. Cis-natural antisense transcripts (cis-NATs) on the other hand are transcribed from the same genomic locus as their target but from the opposite DNA strand and form perfect pairs.
Long non-coding RNAs are a type of RNA, generally defined as transcripts more than 200 nucleotides that are not translated into protein. This arbitrary limit distinguishes long ncRNAs from small non-coding RNAs, such as microRNAs (miRNAs), small interfering RNAs (siRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), and other short RNAs. Long intervening/intergenic noncoding RNAs (lincRNAs) are sequences of lncRNA which do not overlap protein-coding genes.
CDKN2B-AS, also known as ANRIL is a long non-coding RNA consisting of 19 exons, spanning 126.3kb in the genome, and its spliced product is a 3834bp RNA. It is located within the p15/CDKN2B-p16/CDKN2A-p14/ARF gene cluster, in the antisense direction. Single nucleotide polymorphisms (SNPs) which alter the expression of CDKN2B-AS are associated with human healthy life expectancy, as well as with multiple diseases, including coronary artery disease, diabetes and many cancers. It binds to chromobox 7 (CBX7) within the polycomb repressive complex 1 and to SUZ12, a component of polycomb repression complex 2 and through these interactions is involved in transcriptional repression.
In molecular biology, GNAS antisense RNA , also known as GNAS-AS1, is a long non-coding RNA.It is antisense to the GNAS gene. It is an imprinted gene, expressed only from the paternal allele, suggesting that it may have a role in suppression of the paternal NESP55 allele encoded by GNAS.
In molecular biology, HTT antisense RNA 1, also known as HTT-AS1, is a long non-coding RNA. It is an antisense RNA which regulates the expression of the huntingtin gene.
In molecular biology, MEST intronic transcript 1, antisense RNA, also known as MESTIT1 or PEG1-AS is a long non-coding RNA. It is an imprinted gene, which is paternally expressed. In humans, it is found on chromosome 7q32, imprinted genes on chromosome 7 are believed to be involved in Russell-Silver syndrome (RSS). However, it is believed that MESTIT1 is unlikely to cause Russell-Silver syndrome as there is a lack of mutations in this gene in Russell-Silver syndrome patients. MESTIT1 may regulate the expression of the MEST gene.
In molecular biology, RFPL3 antisense RNA 1, also known as RFPL3-AS1 is a long non-coding RNA. In humans, it is on chromosome 22. It is antisense to the RFPL3 gene encoding a RING finger domain-containing protein. It may function in the post-transcriptional regulation of this gene.
In molecular biology, ST7 antisense RNA 1, also known as ST7-AS1 is a long non-coding RNA. In humans, it is found on chromosome 7 in a locus spanning a translocation breakpoint associated with autism. It is antisense to the ST7 gene.
In molecular biology, ST7 overlapping transcript 3, also known as ST7-OT3 is a long non-coding RNA. In humans, it is found on chromosome 7 in a locus spanning a translocation breakpoint associated with autism. It overlaps the ST7 gene, spanning intron 10 to exon 14 of ST7. Some isoforms of ST7 may use exons from ST7-OT3.
In molecular biology, ST7 overlapping transcript 4, also known as ST7-OT4 is a long non-coding RNA. In humans, it is found on chromosome 7 in a locus spanning a translocation breakpoint associated with autism. It contains at least 7 exons and overlaps the ST7 gene.
UBE3A-ATS/Ube3a-ATS (human/mouse), otherwise known as ubiquitin ligase E3A-ATS, is the name for the antisense DNA strand that is transcribed as part of a larger transcript called LNCAT at the Ube3a locus. The Ube3a locus is imprinted and in the central nervous system expressed only from the maternal allele. Silencing of Ube3a on the paternal allele is thought to occur through the Ube3a-ATS part of LNCAT, since non-coding antisense transcripts are often found at imprinted loci. The deletion and/or mutation of Ube3a on the maternal chromosome causes Angelman Syndrome (AS) and Ube3a-ATS may prove to be an important aspect in finding a therapy for this disease. While in patients with AS the maternal Ube3a allele is inactive, the paternal allele is intact but epigenetically silenced. If unsilenced, the paternal allele could be a source of active Ube3a protein in AS patients. Therefore, understanding the mechanisms of how Ube3a-ATS might be involved in silencing the paternal Ube3a may lead to new therapies for AS. This possibility has been demonstrated by a recent study where the drug topotecan, administered to mice suffering from AS, activated expression of the paternal Ube3a gene by lowering the transcription of Ube3a-ATS.
A majority of the human genome is made up of non-protein coding DNA. It infers that such sequences are not commonly employed to encode for a protein. However, even though these regions do not code for protein, they have other functions and carry necessary regulatory information.They can be classified based on the size of the ncRNA. Small noncoding RNA is usually categorized as being under 200 bp in length, whereas long noncoding RNA is greater than 200bp. In addition, they can be categorized by their function within the cell; Infrastructural and Regulatory ncRNAs. Infrastructural ncRNAs seem to have a housekeeping role in translation and splicing and include species such as rRNA, tRNA, snRNA.Regulatory ncRNAs are involved in the modification of other RNAs.
References
- ↑ Vincent JB, Petek E, Thevarkunnel S, Kolozsvari D, Cheung J, Patel M, et al. (2002). "The RAY1/ST7 tumor-suppressor locus on chromosome 7q31 represents a complex multi-transcript system". Genomics. 80 (3): 283–294. doi:10.1006/geno.2002.6835. PMID 12213198.