# EpiTxDb: creating an EpiTxDb object

Felix G.M. Ernst

#### 2021-03-25

#### Package

EpiTxDb 1.2.1

# 1 Introduction

To create an `EpiTxDb` object a number of different functions are available. The most univeral functions are `makeEpiTxDb` and `makeEpiTxDbFromGRanges`. `makeEpiTxDb` uses four `data.frame`s as input, whereas `makeEpiTxDbFromGRanges` is a wrapper for information available as a `GRanges` object.

The other functions are `makeEpiTxDbFromRMBase` and `makeEpiTxDbFromtRNAdb`, which are aimed to make data available from the RMBase v2.0 database (Xuan et al. 2017; Sun et al. 2015) or the tRNAdb (Jühling et al. 2009; Sprinzl and Vassilenko 2005). However, before creating your `EpiTxDb` objects, have a look at the already available resources for `H. sapiens`, `M. musculus` and `S. cerevisiae.`

Additional metadata can be provided as separate `data.frame` for all functions. The `data.frame` must have two columns `name` and `value`.

    library(GenomicRanges)
    library(EpiTxDb)

# 2 `makeEpiTxDb` and `makeEpiTxDbFromGRanges`

The creation of an etdb object is quite easy starting with a `GRanges` object.

    gr <- GRanges(seqnames = "test",
                  ranges = IRanges::IRanges(1,1),
                  strand = "+",
                  DataFrame(mod_id = 1L,
                            mod_type = "Am",
                            mod_name = "Am_1"))
    etdb <- makeEpiTxDbFromGRanges(gr, metadata = data.frame(name = "test",
                                                             value = "Yes"))

    ## Creating EpiTxDb object ... done

    etdb

    ## EpiTxDb object:
    ## # Db type: EpiTxDb
    ## # Supporting package: EpiTxDb
    ## # test: Yes
    ## # Nb of modifications: 1
    ## # Db created by: EpiTxDb package from Bioconductor
    ## # Creation time: 2021-03-25 19:24:13 -0400 (Thu, 25 Mar 2021)
    ## # EpiTxDb version at creation time: 1.2.1
    ## # RSQLite version at creation time: 2.2.4
    ## # DBSCHEMAVERSION: 1.0

    metadata(etdb)

Additional data can be provided via the metadata columns of the `GRanges` object. For supported columns have a look at `?makeEpiTxDb` or `?makeEpiTxDbFromGRanges`.

# 3 `makeEpiTxDbFromtRNAdb`

The information of the tRNAdb can be accessed via the `tRNAdbImport` package using the RNA database. As a result a `ModRNAStringSet` object is returned from which the modifications can be extracted using `separate()`.

The only input require is a valid organism name returned by `listAvailableOrganismsFromtRNAdb()`.

    etdb <- makeEpiTxDbFromtRNAdb("Saccharomyces cerevisiae")

    ## Loading data from tRNAdb ...

    ## Assembling data ...

    ## Creating EpiTxDb object ... done

    etdb

    ## EpiTxDb object:
    ## # Db type: EpiTxDb
    ## # Supporting package: EpiTxDb
    ## # Nb of modifications: 557
    ## # Db created by: EpiTxDb package from Bioconductor
    ## # Creation time: 2021-03-25 19:24:42 -0400 (Thu, 25 Mar 2021)
    ## # EpiTxDb version at creation time: 1.2.1
    ## # RSQLite version at creation time: 2.2.4
    ## # DBSCHEMAVERSION: 1.0

For additional information have a look at `?makeEpiTxDbFromtRNAdb`. The result returned from the tRNAdb is also available as `GRanges` object, if `gettRNAdbDataAsGRanges()` is used.

# 4 `makeEpiTxDbFromRMBase`

Analogous to the example above `makeEpiTxDbFromRMBase()` will download the data from the RMBase v2.0. Three inputs are required, `organism`, `genome` and `modtype`, which have to valid bia the functions `listAvailableOrganismsFromRMBase()`, `.listAvailableGenomesFromRMBase()` and `listAvailableModFromRMBase`.

    etdb <- makeEpiTxDbFromRMBase(organism = "Saccharomyces cerevisiae",
                                  genome = "sacCer3",
                                  modtype = "m1A")

Internally, the files are cached using the `BiocFileCache` package and passed to `makeEpiTxDbFromRMBaseFiles()`, which can also be used with locally stored files. The resuls for creating the `EpiTxDb` class are processed from these files via the `getRMBaseDataAsGRanges()` function.

# 5 Session info

    sessionInfo()

    ## R version 4.0.4 (2021-02-15)
    ## Platform: x86_64-apple-darwin17.0 (64-bit)
    ## Running under: macOS Mojave 10.14.6
    ##
    ## Matrix products: default
    ## BLAS:   /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRblas.dylib
    ## LAPACK: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRlapack.dylib
    ##
    ## locale:
    ## [1] C/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
    ##
    ## attached base packages:
    ## [1] parallel  stats4    stats     graphics  grDevices utils     datasets
    ## [8] methods   base
    ##
    ## other attached packages:
    ##  [1] EpiTxDb_1.2.1        Modstrings_1.6.0     Biostrings_2.58.0
    ##  [4] XVector_0.30.0       AnnotationDbi_1.52.0 Biobase_2.50.0
    ##  [7] GenomicRanges_1.42.0 GenomeInfoDb_1.26.4  IRanges_2.24.1
    ## [10] S4Vectors_0.28.1     BiocGenerics_0.36.0  BiocStyle_2.18.1
    ##
    ## loaded via a namespace (and not attached):
    ##  [1] MatrixGenerics_1.2.1        httr_1.4.2
    ##  [3] sass_0.3.1                  bit64_4.0.5
    ##  [5] jsonlite_1.7.2              bslib_0.2.4
    ##  [7] assertthat_0.2.1            askpass_1.1
    ##  [9] BiocManager_1.30.10         BiocFileCache_1.14.0
    ## [11] blob_1.2.1                  GenomeInfoDbData_1.2.4
    ## [13] Rsamtools_2.6.0             yaml_2.2.1
    ## [15] progress_1.2.2              lattice_0.20-41
    ## [17] pillar_1.5.1                RSQLite_2.2.4
    ## [19] glue_1.4.2                  digest_0.6.27
    ## [21] Structstrings_1.6.1         colorspace_2.0-0
    ## [23] tRNA_1.8.0                  Matrix_1.3-2
    ## [25] htmltools_0.5.1.1           XML_3.99-0.6
    ## [27] pkgconfig_2.0.3             biomaRt_2.46.3
    ## [29] bookdown_0.21               zlibbioc_1.36.0
    ## [31] purrr_0.3.4                 scales_1.1.1
    ## [33] BiocParallel_1.24.1         tibble_3.1.0
    ## [35] openssl_1.4.3               ggplot2_3.3.3
    ## [37] generics_0.1.0              ellipsis_0.3.1
    ## [39] cachem_1.0.4                SummarizedExperiment_1.20.0
    ## [41] GenomicFeatures_1.42.2      magrittr_2.0.1
    ## [43] crayon_1.4.1                memoise_2.0.0
    ## [45] evaluate_0.14               fansi_0.4.2
    ## [47] xml2_1.3.2                  tools_4.0.4
    ## [49] prettyunits_1.1.1           hms_1.0.0
    ## [51] lifecycle_1.0.0             matrixStats_0.58.0
    ## [53] stringr_1.4.0               munsell_0.5.0
    ## [55] tRNAdbImport_1.8.0          DelayedArray_0.16.3
    ## [57] compiler_4.0.4              jquerylib_0.1.3
    ## [59] rlang_0.4.10                grid_4.0.4
    ## [61] debugme_1.1.0               RCurl_1.98-1.3
    ## [63] rappdirs_0.3.3              bitops_1.0-6
    ## [65] rmarkdown_2.7               gtable_0.3.0
    ## [67] DBI_1.1.1                   curl_4.3
    ## [69] R6_2.5.0                    GenomicAlignments_1.26.0
    ## [71] knitr_1.31                  dplyr_1.0.5
    ## [73] rtracklayer_1.50.0          fastmap_1.1.0
    ## [75] bit_4.0.4                   utf8_1.2.1
    ## [77] stringi_1.5.3               Rcpp_1.0.6
    ## [79] vctrs_0.3.6                 dbplyr_2.1.0
    ## [81] tidyselect_1.1.0            xfun_0.22

# References

Jühling, Frank, Mario Mörl, Roland K. Hartmann, Mathias Sprinzl, Peter F. Stadler, and Joern Pütz. 2009. “TRNAdb 2009: Compilation of tRNA Sequences and tRNA Genes.” Nucleic Acids Research 37: D159–D162. https://doi.org/10.1093/nar/gkn772.

Sprinzl, Mathias, and Konstantin S. Vassilenko. 2005. “Compilation of tRNA Sequences and Sequences of tRNA Genes.” Nucleic Acids Research 33: D139–D140. https://doi.org/10.1093/nar/gki012.

Sun, Wen-Ju, Jun-Hao Li, Shun Liu, Jie Wu, Hui Zhou, Liang-Hu Qu, and Jian-Hua Yang. 2015. “RMBase: a resource for decoding the landscape of RNA modifications from high-throughput sequencing data.” Nucleic Acids Research 44 (D1): D259–D265. https://doi.org/10.1093/nar/gkv1036.

Xuan, Jia-Jia, Wen-Ju Sun, Peng-Hui Lin, Ke-Ren Zhou, Shun Liu, Ling-Ling Zheng, Liang-Hu Qu, and Jian-Hua Yang. 2017. “RMBase v2.0: deciphering the map of RNA modifications from epitranscriptome sequencing data.” Nucleic Acids Research 46 (D1): D327–D334. https://doi.org/10.1093/nar/gkx934.