Antisense transcription unit of natural (NAT) is a group of RNA encoded within the cell for transcription complementarity with other RNA transcription. They have been identified in eukaryotic organisms including some Arabidopsis human, mouse, and yeast. It includes both non-coding RNA and protein-coding of this class RNA. This data can be the role of various regulations, RNA interference (RNAi), alternative splicing, to X-chromosome inactivation and genomic printed by this technology. And based on whether or not to act in cis or trans to the rough, NATs’s can be divided into two categories. It is transcribed from elsewhere than its goal, NAT of the transformer, has multiple copies of the supplements and some contradictions usually. The micro RNA (the miRNA), is an example of a transaction that can turn copy NATS and several discrepancies some. Rather than from the same genomic site that purpose, transcribed from DNA strand opposite cis natural antisense transcript (cis NAT), so as to form a perfect pair on the other hand.
The length of the overlap between the pairs and different orientations have different NATs – cis. There are five guidelines to identify the NAT of the Sith to date. Includes two transcripts together 5 ‘end, the most frequent and posture of the head to head. Lead to knock down the largest of gene expression in transcription orientation collision reason look up suppression such. However, tail shows that there is some research – the direction of the tail overlap, as the tail of the tail, NAT. Near the tail, it is less common to tail in pairs the most common other, and close to the head-to-head. On top of each other to include antisense gene is full, head near complete duplication NATs – head and tail – the direction of the tail are physically separated from one another, but are very close to each other. I have shown that there is overrepresentation of NAT pair of genes data has a catalytic activity. In particular can be, it becomes more susceptible to them for this type of adjustment, this has something to these genes.
Identification of NAT of all genome, is possible thanks to a large collection of sequence data available from different organisms. Depending on the source of sequence information, a method for detecting the NAT on in silico suffer from several drawbacks. research is mRNA sequence orientation is known, using the amount of available mRNA sequence information is small. Model was estimated using the training genetic algorithm to determine a gene, provides coverage with increased genome of the cost of the gene in trust. Another input is a library (EST) wide expressed sequence tagging, but before you can extract from it useful information orientation, you must first determine a small sequence of these. If you are using the EST special sequence information, such as splice sites for both filters EST poly (A) signal, and a poly A tail, Several studies have obtained the right direction of transcription them. increase the coverage, a combination of the source sequence that differs, trying to maintain the integrity of the data.
Pairs of NATs when forming the clusters they overlap are identified. In general, ~ is considered the transcript of 20 nucleotides of sequence overlap, usage restrictions in research volatility variety there is, is considered the minimum for the cluster overlap. Further, as can be regarded NAT pair of copying correlates with mRNA molecules of each other it. It can be used to find antisense pairs Currently there are various resources or software web. Database antisense transcript or natural NATsdb is a search tool a pointless couple wealth from a variety of organisms.
Molecular mechanisms behind the regulatory role of NAT in cis are not fully understood at present. It has been proposed to explain the regulatory effects having a NAT model gene expression cis three. In knockdown of mRNA expression and cis-NAT model attributes of the first, pairing between the transcript result complementary. It is that there will be arranged a six base pairs, at least between the pair of cis-NAT to make the double-stranded RNA only assumption of this model. Epigenetic modifications, such as post-translational modifications of histone and DNA methylation such, has become a major base for the second model. It has not been clearly understood yet, it is meant the inhibition of gene expression and reverse transcription complex guide methylation and / or it is considered that histone modifications complexes to the promoter region of the reference lead. It is important for not known what attributes of the NAT system of current regulatory model epigenetic. Proposed model and the last, have gained favor in the transcription collision model based on experimental evidence of recent. In the course of the transfer of the NAT of the Sith, transcription complex, gather in the promoter region of the gene. On the determination of the nucleotide in the direction ‘to 3’ 5, RNA polymerase, to initiate recording of the gene of the transcription start site. Cis – and collide in the region of overlap between the RNA polymerase NATs, stopped at the crash site. For its premature stop incomplete transcript and fall RNA polymerase, transcription is suppressed.