Mycobacterium tuberculosis sRNA
Encyclopedia

Mycobactierum tuberculosis contains at least nine small RNA
Bacterial small RNA
Bacterial small RNAs are small non-coding RNA molecules produced by bacteria, they are highly structured and contain several stem-loops...

 families in its genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

. The small RNA (sRNA) families were identified through RNomics - the direct analysis of RNA molecules isolated from cultures
Cell culture
Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from singlecellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes,...

 of Mycobacterium tuberculosis
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a pathogenic bacterial species in the genus Mycobacterium and the causative agent of most cases of tuberculosis . First discovered in 1882 by Robert Koch, M...

. The sRNAs were characterised through RACE mapping and Northern blot
Northern blot
The northern blot is a technique used in molecular biology research to study gene expression by detection of RNA in a sample. With northern blotting it is possible to observe cellular control over structure and function by determining the particular gene expression levels during differentiation,...

 experiments. Secondary structures
Secondary structure
In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

 of the sRNAs were predicted using Mfold.

sRNAPredict2 - a bioinformatics
Bioinformatics
Bioinformatics is the application of computer science and information technology to the field of biology and medicine. Bioinformatics deals with algorithms, databases and information systems, web technologies, artificial intelligence and soft computing, information and computation theory, software...

 tool - suggested 56 putative sRNAs in M. tuberculosis, though these have yet to be verified experimentally. Hfq protein
Hfq protein
The Hfq protein encoded by the hfq gene was discovered in 1968 as an Escherichia. coli host factor that was essential for replication of the bacteriophage Qβ. It is now clear that Hfq is an abundant bacterial RNA binding protein which has many important physiological roles. Usually mediated by...

 homologues have yet to be found in M. tuberculosis; an alternative pathway - potentially involving conserved C
Cytosine
Cytosine is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine . It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached . The nucleoside of cytosine is cytidine...

-rich motifs - has been theorised to enable trans-acting
Trans-acting
In the field of molecular biology, trans-acting , in general, means "acting from a different molecule"...

 sRNA functionality.

sRNAs were shown to have important physiological
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 roles in M. tuberculosis. Overexpression of G2 sRNA, for example, prevented growth of M. tuberculosis and greatly reduced the growth of M. smegmatis
Mycobacterium smegmatis
Mycobacterium smegmatis is 3.0 to 5.0 µm long with a bacillus shape, an acid-fast bacterial species in the phylum Actinobacteria. It can be stained by Ziehl-Neelsen method and the auramine-rhodamine fluorescent method. It was first reported in November 1884 by Lustgarten, who found a bacillus...

; ASdes sRNA is thought to be a cis-acting regulator of a fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...

 desaturase (desA2) while ASpks is found with the open reading frame
Open reading frame
In molecular genetics, an open reading frame is a DNA sequence that does not contain a stop codon in a given reading frame.Normally, inserts which interrupt the reading frame of a subsequent region after the start codon cause frameshift mutation of the sequence and dislocate the sequences for stop...

 for Polyketide synthase
Polyketide synthase
Polyketide synthases are a family of multi-domain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages...

-12 (pks12) and is an antisense regulator of pks12 mRNA.

See also

  • Bacterial small RNA
    Bacterial small RNA
    Bacterial small RNAs are small non-coding RNA molecules produced by bacteria, they are highly structured and contain several stem-loops...

  • Caenorhabditis elegans sRNA
    C. elegans small RNAs
    Small RNAs have been identified within the C. elegans genome and comparative genomics has shown that they are conserved across several nematode species. These sRNAs contain a characteristic 2,2,7-trimethylguanosine cap structure that identifies them as non-coding RNAs that have a functional role...

  • Bacillus subtilis sRNAs
    Bacillus subtilis BSR sRNAs
    In a screen of the Bacillus subtilis genome for genes encoding ncRNAs, Saito et al. focused on 123 intergenic regions over 500 bp in length, the authors analyzed expression from these regions. Seven IGRs termed bsrC, bsrD, bsrE, bsrF, bsrG, bsrH and bsrI expressed RNAs smaller than 380 nt...

  • Escherichia coli sRNA
    Escherichia coli sRNA
    Escherichia coli contains a number of small RNAs located in intergenic regions of its genome. The presence of at least 55 of these has been verfied experimentally. 275 potential sRNA-encoding loci were identified computationally using the QRNA program. These loci will include false positives, so...

  • Pseudomonaa sRNA
    Pseudomonas sRNA
    Pseudomonas sRNA are non-coding RNAs that were predicted by the bioinformatic program SRNApredict2. This program identifies putative sRNAs by searching for co-localization of genetic features commonly associated with sRNA-encoding genes and the expression of the predicted sRNAs was subsequently...



Further reading

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