diff --git a/NEWS.md b/NEWS.md
index aadbca6..600c000 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,9 @@
 # Upcoming changes in version 2.11.4
 
+BACKWARDS-INCOMPATIBLE CHANGES
+
+- The `range` argument of the `annotateCTSS` function is renamed `annot`.
+
 NEW FEATURES
 
 -   Support the use of `TxDB` objects for annotating clusters.
diff --git a/R/Annotations.R b/R/Annotations.R
index 31e9b5d..5f69854 100644
--- a/R/Annotations.R
+++ b/R/Annotations.R
@@ -408,15 +408,21 @@ msScope_annotation <- function(libs) {
 #' 
 #' @param object `CAGEexp` object.
 #'   
-#' @param ranges A [`GRanges`] object, optionally containing `gene_name`,
-#'   `type` and `transcript_type` metadata.
+#' @param annot A [`GRanges`] or a [`TxDb`] object representing the genome
+#'               annotation.  See details for the `GRanges` object.
 #' 
 #' @param upstream Number of bases _upstream_ the start of the transcript models
 #'        to be considered as part of the _promoter region_.
 #'        
 #' @param downstream Number of bases _downstream_ the start of the transcript
 #'        models to be considered as part of the _promoter region_.
-#'   
+#' 
+#' @details
+#' If the annotation is a [`GRanges`], gene names will be extracted from the
+#' `gene_name` metadata, the `transcript_type` metadata will be used to filter
+#' out entries that do not have promoters (such as immunogloblulin VDJ segments),
+#' and the `type` metadata is used to extract positions of introns and exons.
+#' 
 #' @return `annotateCTSS` returns the input object with the following
 #'   modifications:
 #' 
@@ -444,14 +450,14 @@ msScope_annotation <- function(libs) {
 #' 
 #' @export
 
-setGeneric("annotateCTSS", function(object, ranges, upstream=500, downstream=500)
+setGeneric("annotateCTSS", function(object, annot, upstream=500, downstream=500)
   standardGeneric("annotateCTSS"))
 
 #' @rdname annotateCTSS
 
-setMethod("annotateCTSS", c("CAGEexp", "GRanges"), function (object, ranges, upstream=500, downstream=500){
-  CTSScoordinatesGR(object)$genes      <- ranges2genes(CTSScoordinatesGR(object), ranges)
-  CTSScoordinatesGR(object)$annotation <- ranges2annot(CTSScoordinatesGR(object), ranges, upstream, downstream)
+setMethod("annotateCTSS", c("CAGEexp", "GRanges"), function (object, annot, upstream=500, downstream=500){
+  CTSScoordinatesGR(object)$genes      <- ranges2genes(CTSScoordinatesGR(object), annot)
+  CTSScoordinatesGR(object)$annotation <- ranges2annot(CTSScoordinatesGR(object), annot, upstream, downstream)
   
   annot <- sapply( CTSStagCountDF(object)
                  , function(X) tapply(X, CTSScoordinatesGR(object)$annotation, sum))
@@ -463,20 +469,32 @@ setMethod("annotateCTSS", c("CAGEexp", "GRanges"), function (object, ranges, ups
 
 #' @rdname annotateCTSS
 
-setMethod("annotateCTSS", c("CAGEexp", "TxDb"), function (object, ranges){
-  g <- genes(ranges)
-  g$gene_name <- g$gene_id
-  annotateCTSS(object, g)
-  CTSScoordinatesGR(object)$genes      <- ranges2genes(CTSScoordinatesGR(object), g)
-  CTSScoordinatesGR(object)$annotation <- txdb2annot(CTSScoordinatesGR(object), ranges)
-  
-  annot <- sapply( CTSStagCountDF(object)
-                   , function(X) tapply(X, CTSScoordinatesGR(object)$annotation, sum))
-  colData(object)[levels(CTSScoordinatesGR(object)$annotation)] <- DataFrame(t(annot))
-  validObject(object)
-  object
+setMethod("annotateCTSS", c("CAGEexp", "TxDb"), function (object, annot){
+  annotateCTSS(object, .txdb2annotranges(annot))
 })
 
+#' @name .txdb2annotranges
+#' 
+#' @noRd
+#' 
+#' @importFrom GenomicFeatures promoters exons transcripts
+#' 
+#' @examples
+#' txdb_file <- system.file("extdata", "hg19_knownGene_sample.sqlite",
+#'                          package="GenomicFeatures")
+#' txdb <- loadDb(txdb_file)
+#' .txdb2annotranges(txdb)
+
+.txdb2annotranges <- function(txdb) {
+  t <- transcripts(txdb, columns=c("gene_id"))
+  t$type <- "transcript"
+  e <- exons(txdb, columns=c("gene_id"))
+  e$type <- "exon"
+  annot <- c(t,e)
+  annot$gene_name <- annot$gene_id
+  annot
+}
+
 #' `annotateTagClusters` annotates the _tag clusters_ of a _CAGEr_ object.
 #'   
 #' @return `annotateTagClusters` returns the input object with the same
@@ -489,24 +507,29 @@ setMethod("annotateCTSS", c("CAGEexp", "TxDb"), function (object, ranges){
 #' @export
 #' @rdname annotateCTSS
 
-setGeneric("annotateTagClusters", function(object, ranges, upstream=500, downstream=500)
+setGeneric("annotateTagClusters", function(object, annot, upstream=500, downstream=500)
   standardGeneric("annotateTagClusters"))
 
 #' @rdname annotateCTSS
 
-setMethod("annotateTagClusters", c("CAGEexp", "GRanges"), function (object, ranges, upstream=500, downstream=500){
+setMethod("annotateTagClusters", c("CAGEexp", "GRanges"), function (object, annot, upstream=500, downstream=500){
   if(is.null(experiments(object)$tagCountMatrix))
     stop("Input does not contain CTSS expressiond data, see ", dQuote("getCTSS()"), ".")
   tagClustersGR(object) <- endoapply(tagClustersGR(object), function (gr) {
-    gr$annotation <- ranges2annot(gr, ranges, upstream, downstream) 
-    if(!is.null(ranges$gene_name))
-      gr$genes    <- ranges2genes(gr, ranges)
+    gr$annotation <- ranges2annot(gr, annot, upstream, downstream) 
+    if(!is.null(annot$gene_name))
+      gr$genes    <- ranges2genes(gr, annot)
     gr
     })
   validObject(object)
   object
 })
 
+#' @rdname annotateCTSS
+
+setMethod("annotateTagClusters", c("CAGEexp", "TxDb"), function (object, annot){
+  annotateTagClusters(object, .txdb2annotranges(annot))
+})
 
 #' @name annotateConsensusClusters
 #' 
@@ -524,21 +547,24 @@ setMethod("annotateTagClusters", c("CAGEexp", "GRanges"), function (object, rang
 #' 
 #' @export
 
-setGeneric("annotateConsensusClusters", function(object, ranges, upstream=500, downstream=500)
+setGeneric("annotateConsensusClusters", function(object, annot, upstream=500, downstream=500)
   standardGeneric("annotateConsensusClusters"))
 
 #' @rdname annotateCTSS
 
-setMethod("annotateConsensusClusters", c("CAGEexp", "GRanges"), function (object, ranges, upstream=500, downstream=500){
-  if(is.null(experiments(object)$tagCountMatrix))
-    stop("Input does not contain CTSS expressiond data, see ", dQuote("getCTSS()"), ".")
-  consensusClustersGR(object)$annotation <- ranges2annot(consensusClustersGR(object), ranges, upstream, downstream)
-  if(!is.null(ranges$gene_name))
-    consensusClustersGR(object)$genes    <- ranges2genes(consensusClustersGR(object), ranges)
+setMethod("annotateConsensusClusters", c("CAGEexp", "GRanges"), function (object, annot, upstream=500, downstream=500){
+  consensusClustersGR(object)$annotation <- ranges2annot(consensusClustersGR(object), annot, upstream, downstream)
+  if(!is.null(annot$gene_name))
+    consensusClustersGR(object)$genes    <- ranges2genes(consensusClustersGR(object), annot)
   validObject(object)
   object
 })
 
+#' @rdname annotateCTSS
+
+setMethod("annotateConsensusClusters", c("CAGEexp", "TxDb"), function (object, annot){
+  annotateConsensusClusters(object, .txdb2annotranges(annot))
+})
 
 #' Hierarchical annotation of genomic regions.
 #' 
@@ -637,34 +663,6 @@ ranges2annot <- function(ranges, annot, upstream=500, downstream=500) {
   Rle(annot)
 }
 
-#' @name txdb2annot
-#' 
-#' @rdname ranges2annot
-#' 
-#' @importFrom GenomicFeatures promoters exons transcripts
-
-txdb2annot <- function(ranges, annot) {
-  findOverlapsBool <- function(A, B) {
-    overlap <- findOverlaps(A, B)
-    overlap <- as(overlap, "List")
-    any(overlap)
-  }
-  
-  classes <- c("promoter", "exon", "intron", "unknown")
-  p <- findOverlapsBool(ranges, trim(suppressWarnings(promoters(annot, 500, 500))))
-  e <- findOverlapsBool(ranges, exons(annot))
-  t <- findOverlapsBool(ranges, transcripts(annot))
-  annot <- sapply( 1:length(ranges), function(i) {
-    if      (p[i]) {classes[1]}
-    else if (e[i]) {classes[2]}
-    else if (t[i]) {classes[3]}
-    else           {classes[4]}
-  })
-  
-  annot <- factor(annot, levels = classes)
-  Rle(annot)
-}
-
 #' ranges2genes
 #' 
 #' Assign gene symbol(s) to Genomic Ranges.
diff --git a/man/annotateCTSS.Rd b/man/annotateCTSS.Rd
index 8d488d5..ad501da 100644
--- a/man/annotateCTSS.Rd
+++ b/man/annotateCTSS.Rd
@@ -6,29 +6,35 @@
 \alias{annotateCTSS,CAGEexp,TxDb-method}
 \alias{annotateTagClusters}
 \alias{annotateTagClusters,CAGEexp,GRanges-method}
+\alias{annotateTagClusters,CAGEexp,TxDb-method}
 \alias{annotateConsensusClusters}
 \alias{annotateConsensusClusters,CAGEexp,GRanges-method}
+\alias{annotateConsensusClusters,CAGEexp,TxDb-method}
 \title{Annotate and compute summary statistics}
 \usage{
-annotateCTSS(object, ranges, upstream = 500, downstream = 500)
+annotateCTSS(object, annot, upstream = 500, downstream = 500)
 
-\S4method{annotateCTSS}{CAGEexp,GRanges}(object, ranges, upstream = 500, downstream = 500)
+\S4method{annotateCTSS}{CAGEexp,GRanges}(object, annot, upstream = 500, downstream = 500)
 
-\S4method{annotateCTSS}{CAGEexp,TxDb}(object, ranges)
+\S4method{annotateCTSS}{CAGEexp,TxDb}(object, annot)
 
-annotateTagClusters(object, ranges, upstream = 500, downstream = 500)
+annotateTagClusters(object, annot, upstream = 500, downstream = 500)
 
-\S4method{annotateTagClusters}{CAGEexp,GRanges}(object, ranges, upstream = 500, downstream = 500)
+\S4method{annotateTagClusters}{CAGEexp,GRanges}(object, annot, upstream = 500, downstream = 500)
 
-annotateConsensusClusters(object, ranges, upstream = 500, downstream = 500)
+\S4method{annotateTagClusters}{CAGEexp,TxDb}(object, annot)
 
-\S4method{annotateConsensusClusters}{CAGEexp,GRanges}(object, ranges, upstream = 500, downstream = 500)
+annotateConsensusClusters(object, annot, upstream = 500, downstream = 500)
+
+\S4method{annotateConsensusClusters}{CAGEexp,GRanges}(object, annot, upstream = 500, downstream = 500)
+
+\S4method{annotateConsensusClusters}{CAGEexp,TxDb}(object, annot)
 }
 \arguments{
 \item{object}{\code{CAGEexp} object.}
 
-\item{ranges}{A \code{\link{GRanges}} object, optionally containing \code{gene_name},
-\code{type} and \code{transcript_type} metadata.}
+\item{annot}{A \code{\link{GRanges}} or a \code{\link{TxDb}} object representing the genome
+annotation.  See details for the \code{GRanges} object.}
 
 \item{upstream}{Number of bases \emph{upstream} the start of the transcript models
 to be considered as part of the \emph{promoter region}.}
@@ -64,6 +70,12 @@ annotation statistics.
 \code{annotateConsensusClusters} annotates the \emph{consensus clusters}
 of a CAGEr object.
 }
+\details{
+If the annotation is a \code{\link{GRanges}}, gene names will be extracted from the
+\code{gene_name} metadata, the \code{transcript_type} metadata will be used to filter
+out entries that do not have promoters (such as immunogloblulin VDJ segments),
+and the \code{type} metadata is used to extract positions of introns and exons.
+}
 \examples{
 annotateCTSS(exampleCAGEexp, exampleZv9_annot)
 colData(exampleCAGEexp)
diff --git a/man/ranges2annot.Rd b/man/ranges2annot.Rd
index 2c17910..180c0ed 100644
--- a/man/ranges2annot.Rd
+++ b/man/ranges2annot.Rd
@@ -2,12 +2,9 @@
 % Please edit documentation in R/Annotations.R
 \name{ranges2annot}
 \alias{ranges2annot}
-\alias{txdb2annot}
 \title{Hierarchical annotation of genomic regions.}
 \usage{
 ranges2annot(ranges, annot, upstream = 500, downstream = 500)
-
-txdb2annot(ranges, annot)
 }
 \arguments{
 \item{ranges}{A \code{\link[GenomicRanges:GRanges-class]{GenomicRanges::GRanges}} object, for example extracted from