Giant, Ornate, Lake- and Lactobacillales-Derived (GOLLD) RNA is a conserved RNA structure present in bacteria. GOLLD RNAs were originally detected based on metagenome sequences of DNA isolated from Lake Gatun in Panama. However, they are known to be present in at least eight strains of cultivated bacteria. GOLLD RNAs are extraordinarily large compared to other RNAs with a conserved, complex secondary structure, and average roughly 800 nucleotides. Such large, complex RNAs are often ribozymes, although the biochemical function of GOLLD RNAs remains unknown. The discovery of large RNAs like GOLLD RNAs among bacteria that are mostly uncultivated under laboratory conditions suggests that many other unusually large RNAs might be found in bacteria that have not yet been studied.
HNH Endonuclease-Associated RNA and ORF (HEARO) RNAs conform to a conserved RNA structure that was identified in bacteria by bioinformatics. HEARO RNAs average roughly 300 nucleotides, which is comparable to the size of many ribozymes, which catalyze chemical reactions.
A wide variety of non-coding RNAs have been identified in various species of organisms known to science. However, RNAs have also been identified in "metagenomics" sequences derived from samples of DNA or RNA extracted from the environment, which contain unknown species. Initial work in this area detected homologs of known bacterial RNAs in such metagenome samples. Many of these RNA sequences were distinct from sequences within cultivated bacteria, and provide the potential for additional information on the RNA classes to which they belong.
The IMES-1 RNA motif is a conserved RNA structure that was identified in marine environmental sequences by two studies based on metagenomics and bioinformatics, the first analyzing metatranscriptome (RNA) data and the second using metagenome (DNA) data. These RNAs are present in environmental sequences, and as of 2009 are not known to be present in any cultivated species. However, the species that use these RNAs are most closely related to known alphaproteobacteria and gammaproteobacteria. IMES-1 RNAs make up a significant portion of marine RNA transcripts and are exceptionally abundant in that over five times as many IMES-1 RNAs were found as ribosomes in RNAs sampled from the Pacific Ocean. Only two bacterial RNAs are known to be more highly transcribed than ribosomes. IMES-1 RNAs were also detected in abundance in Block Island Sound in the Atlantic Ocean.
The IMES-2 RNA motif is a conserved RNA structure that was identified by a study based on metagenomics and bioinformatics, and the underlying RNA sequences were identified independently by a similar earlier study. These RNAs are present in environmental sequences, and when discovered were not known to be present in any cultivated species. However, an IMES-2 RNA has been detected in alphaproteobacterium HIMB114, which is classified in the SAR11 clade of marine bacteria. This finding fits with earlier predictions that species that use IMES-2 RNAs are most closely related to alphaproteobacteria. IMES-2 RNAs are exceptionally abundant, as twice as many IMES-2 RNAs were found as ribosomes in RNAs sampled from the Pacific Ocean. Only two bacterial RNAs are known to be more highly transcribed than ribosomes.
The IMES-3 RNA motif is a conserved RNA structure that was identified based on metagenomics and bioinformatics, and the underlying RNA sequences were identified independently by an earlier study. These RNAs are present in environmental sequences, and as of 2009 are not known to be present in any cultivated species. IMES-3 RNAs are abundant in comparison to ribosomes in RNAs sampled from the Pacific Ocean.
The IMES-4 RNA motif is a conserved RNA structure that was identified in marine environmental sequences by metagenomics and bioinformatics. These RNAs are present in environmental sequences, and as of 2009 are not known to be present in any cultivated species. IMES-4 RNAs are fairly abundant in comparison to ribosomes in RNAs sampled from the Pacific Ocean.
The c4 antisense RNA is a non-coding RNA used by certain phages that infect bacteria. It was initially identified in the P1 and P7 phages of E. coli. The identification of c4 antisense RNAs solved the mystery of the mechanism for regulation of the ant gene, which is an anti-repressor.
The Dictyoglomi-1 RNA motif is a conserved RNA structure that was discovered via bioinformatics. Only four instances of the RNA were detected, and all are in the bacterial phylum Dictyoglomota, whose members have not been extensively studied. The RNA might have a cis-regulatory role, but the evidence is ambiguous. Because of the few instances of Dictyoglomi-1 RNAs known, it is also unknown whether the RNA structure might extend further in the 5′ or 3′ direction, or in both directions.
The Gut-1 RNA motif is a conserved RNA structure identified by bioinformatics. These RNAs are present in environmental sequences, and as of 2010 are not known to be present in any species that has been grown under laboratory conditions. Gut-1 RNA is exclusively found in DNA from uncultivated bacteria present in samples from the human gut.
The manA RNA motif refers to a conserved RNA structure that was identified by bioinformatics. Instances of the manA RNA motif were detected in bacteria in the genus Photobacterium and phages that infect certain kinds of cyanobacteria. However, most predicted manA RNA sequences are derived from DNA collected from uncultivated marine bacteria. Almost all manA RNAs are positioned such that they might be in the 5' untranslated regions of protein-coding genes, and therefore it was hypothesized that manA RNAs function as cis-regulatory elements. Given the relative complexity of their secondary structure, and their hypothesized cis-regulatory role, they might be riboswitches.
The wcaG RNA motif is an RNA structure conserved in some bacteria that was detected by bioinformatics. wcaG RNAs are found in certain phages that infect cyanobacteria. Most known wcaG RNAs were found in sequences of DNA extracted from uncultivated marine bacteria. wcaG RNAs might function as cis-regulatory elements, in view of their consistent location in the possible 5' untranslated regions of genes. It was suggested the wcaG RNAs might further function as riboswitches.
The Termite-flg RNA motif is a conserved RNA structure identified by bioinformatics. Genomic sequences corresponding to Termite-flg RNAs have been identified only in uncultivated bacteria present in the termite hindgut. As of 2010 it has not been identified in the DNA of any cultivated species, and is thus an example of RNAs present in environmental samples.
The Whalefall-1 RNA motif refers to a conserved RNA structure that was discovered using bioinformatics. Structurally, the motif consists of two stem-loops, the second of which is often terminated by a CUUG tetraloop, which is an energetically favorable RNA sequence. Whalefall-1 RNAs are found only in DNA extracted from uncultivated bacteria found on whale fall, i.e., a whale carcass. As of 2010, Whalefall-1 RNAs have not been detected in any known, cultivated species of bacteria, and are thus one of several RNAs present in environmental samples.
The yjdF RNA motif is a conserved RNA structure identified using bioinformatics. Most yjdF RNAs are located in bacteria classified within the phylum Bacillota. A yjdF RNA is found in the presumed 5' untranslated region of the yjdF gene in Bacillus subtilis, and almost all yjdF RNAs are found in the 5' UTRs of homologs of this gene. The function of the yjdF gene is unknown, but the protein that it is predicted to encode is classified by the Pfam Database as DUF2992.
RNAs Associated with Genes Associated with Twister and Hammerhead ribozymes (RAGATH) refers to a bioinformatics strategy that was devised to find self-cleaving ribozymes in bacteria. It also refers to candidate RNAs, or RAGATH RNA motifs, discovered using this strategy.
The Ocean-VII RNA motif is a conserved RNA structure that was discovered by bioinformatics. Ocean-VII motifs are found in metagenomic sequences isolated from various marine environments, and are not yet known in any classified organism. This environmental context is similar to other marine RNAs that were found previously by predominantly bioinformatic or experimental methods.
The salivarius-1 RNA motif is a conserved RNA structure that was discovered by bioinformatics. The salivarius-1 motif occurs in various strains of the species Lactobacillus salivarius, as well as some metagenomic sequences that come from unknown species. salivarius-1 RNAs likely function in trans as small RNAs. While most salivarius-1 RNAs are upstream of protein-coding genes, which could suggest a function as cis-regulatory elements, the downstream gene is often located far away. Curiously, salivarius-1 RNAs are often located nearby to other salivarius-1 RNAs.
The ssNA-helicase RNA motif is a conserved RNA structure that was discovered by bioinformatics. Although the ssNA-helicase motif was published as an RNA candidate, there is some reason to suspect that it might function as a single-stranded DNA. In terms of secondary structure, RNA and DNA are difficult to distinguish when only sequence information is available.
The uup RNA motif is a conserved RNA structure that was discovered by bioinformatics. uup motif RNAs are found in Bacillota and Gammaproteobacteria.
