We are pleased to announce RNAcentral Release 27, which now contains more than 55 million sequences, an increase of approximately 10 million sequences since the previous release.
For the first time, RNAcentral includes expert databases for circular RNAs (circRNAs), CIRCpedia and circAtlas. We also welcome mirtronDB, which provides mirtrons, a subclass of miRNAs derived from small introns, and JaponicusDB, which contributes RNA sequences from the fission yeast Schizosaccharomyces japonicus.
This release also expands RNAcentral's quality-control capabilities with two new tools for identifying potential protein-coding regions, tcode and stopfree, alongside a new QC summary table. These complement the existing CPAT, contamination, and Rfam quality-control checks.
We have expanded our RNA gene annotations to cover more than 800 species and introduced several improvements to the website, including a new track hub displaying Sci-ModoM RNA modifications in the IGV browser and data exports in Parquet format.
Data
New databases
JaponicusDB date imported 2026-06-23
CIRCpedia v3
circAtlas 3.0
Sci-ModoM (via MODOMICS) imported 2026-06
mirtronDB 2.0
Database updates
These databases were updated in this release to the version stated below:
ENA 2025-03-06 -> 2026-05-15
Rfam 15.0 -> 15.1
Ensembl 113 -> 115
Ensembl Fungi 60 -> 62
Ensembl Metazoa 60 -> 62
Ensembl Plants 60 -> 62
Ensembl Protists 60 -> 62
Ensembl/GENCODE human 47/mouse M34 -> human 49/mouse M38
Expression Atlas 2025-04-01 -> 2026-06-23
FlyBase FB2025_01 -> FB2026_01
GeneCards 5.23 -> 5.26
HGNC 2025-03-06 -> 2026-04-28
IntAct 2024-11-05 -> 2026-04-13
MalaCards 5.23 -> 5.26
PDBe 2024-11-05 -> 2026-04-29
PomBase 2024-11-05 -> 2026-04-28
QuickGo 2024-11-05 -> 2026-04-13
RefSeq 2025-03-06 -> 2026-03-25 (v235)
SGD 2025-03-06 -> 2026-03-26
WormBase 2025-03-06 -> 2026-05-15
ZFIN 2024-11-05 -> 2026-03-27
TAIR 10 -> 12
gtRNAdb 21 -> 22
RGD March 2018 -> 2026-04-28
SILVA 138.1 -> 138.2
MGNIFY 2025-03-06 -> 2026-04-13
MODOMICS 2024 -> 2025
EVLNCRNAS 2.0 -> 3.0
REDIportal 2.0 -> 3.0
New gene-level entries
We have expanded the spectrum of species covered for genes, going from ~107k non-coding RNA genes (203 species, release 26) to a total of >1M genes (>800 species) in the current release.
AI-generated summaries for transcripts are now visible on the gene pages as well. For more information about gene-level entries, check our NAR 2026 paper.
Expanded coding-potential detection
This release strengthens RNAcentral's quality control with two new coding-potential tools and a new summary table. Alongside the existing CPAT check, we now run tcode (EMBOSS v6.6.0), which applies the Fickett TESTCODE statistic across all organisms on sequences longer than 200 nt, and stopFree, an in-house Rust implementation that measures the longest stop-codon-free run in each reading frame, run on all sequences. To make these results easy to interpret, we have also introduced a quality-control summary table in the QC Status section, letting users assess a sequence at a glance. It reports coding potential, contamination, and Rfam checks, with a green tick for a pass and a red cross for a fail. The coding-potential row can be expanded to show the individual CPAT, tcode, and stopFree results, and displays an amber status when the three methods disagree. We acknowledge the inspiration from the benchmarking study Evaluating computational tools for protein-coding sequence detection: Are they up to the task? by Paul Gardner and colleagues, which informed our choice of coding-potential tools.
Litscan updates
Litscan has been updated to scan 23,032,875 ids across 1,509,944 papers. LitScan searches the scientific literature for mentions of RNAcentral identifiers and related terms (such as gene names, synonyms, and database accessions), surfacing publications relevant to each sequence.
We have extended LitScan's literature coverage to additional expert databases, including TarBase, LncBook, and DictyBase. By adding tailored queries for these databases, we improve the discovery of literature linked to their entries, for example matching gene synonyms such as LINC01786 for LncBook, or accessions and RNA names for TarBase and DictyBase.
RNAcentral MCP server
This release introduces the RNAcentral MCP Server, which exposes the RNAcentral database as tools that large language models can call directly. Built on the Model Context Protocol, it lets AI assistants query ncRNA sequences, map identifiers, find ncRNAs overlapping genomic regions, retrieve 2D structures, export sequences (FASTA or Parquet), and access literature summaries, orchestrating several upstream APIs so a single question is answered with one tool call.
It is published on PyPI as rnacentral-mcp-server, and listed in BioContextAI, a community effort to connect agentic AI with biomedical resources using the MCP. See the documentation for setup with Claude Desktop, Claude Code, and other clients.
Website updates
Sci-ModoM tracks with RNA modifications and highlighted transcripts in IGV
Sci-ModoM, the first next-generation RNome database offering a holistic view of the epitranscriptomic landscape. Sci-ModoM contains 7,952,319 reported sites with stoichiometric information across 163 datasets, for genome assemblies GRCh38 (human) and GRCm39 (mouse) [2026-06-15], provided in bedRMod format. We have made these RNA annotation variants available in a track hub in the IGV genome browser. In addition, finding the transcript you're viewing within the embedded IGV genome browser is now much easier. The transcript of interest is highlighted in yellow, so it stands out from the other transcripts in the same genomic region rather than blending in. This is a small change that makes navigating the genome browser on a transcript page noticeably quicker.

Example for human small nucleolar RNA host gene 29 (SNHG29)
https://rnacentral.org/rna/URS000075BC33/9606
Example for human small nucleolar RNA host gene 29 (SNHG29)
https://rnacentral.org/rna/URS000075BC33/9606
Filtering in the Molecular Relationships tab

Molecular relationships tab for human SNHG29.
Molecular relationships tab for human SNHG29.
Export search results to Hugging Face in Parquet format
You can now export a set of search results directly as a Hugging Face dataset in Parquet format, ready for machine-learning workflows. From the export options, the chosen selection of sequences is packaged as Parquet (with an accompanying dataset README) and made available on the Hugging Face Hub, making it easy to build training or analysis datasets from RNAcentral without any manual conversion. Parquet is also offered as a standard download format for search exports.
Other web updates
Faster sequence search: Sequence search now runs on EMBL-EBI's Job Dispatcher service, making it quicker and more robust. RNAcentral sequence search using HMMER3 nhmmer has also been added to the Job Dispatcher tools listing, alongside EMBL-EBI's other search and analysis services.
Species-subsetted FASTA files on the FTP: we now provide separate FASTA files for species with more than 100 sequences in addition to a file containing all active sequences.
New version of R2DT deployed on the web app: The R2DT web widget has been updated to version 2.0.0, which guarantees the generation of non-overlapping diagrams.
AI-generated summaries from the API: These are now labelled "WARNING: This summary was generated by AI" when retrieved from the API.
New preview cards for RNAcentral URLs: When an RNAcentral link is shared (for example on social media), it now displays a meaningful preview card showing the page title and description, instead of a generic logo.
Get in touch
As always, all data are freely available on the RNAcentral website, via the API, our public database, and in the FTP archive. If you have any feedback, please get in touch by email, Bluesky, LinkedIn, or by submitting an issue on GitHub. We look forward to hearing from you!
As always, all data are freely available on the RNAcentral website, via the API, our public database, and in the FTP archive. If you have any feedback, please get in touch by email, Bluesky, LinkedIn, or by submitting an issue on GitHub. We look forward to hearing from you!