RT Journal
A1 Rodriguez, Antony
A1 Griffiths-Jones, Sam
A1 Ashurst, Jennifer L.
A1 Bradley, Allan
T1 Identification of Mammalian microRNA Host Genes and Transcription Units
JF Genome Research 
JO Genome Research 
YR 2004 
FD October 01 
VO 14 
IS 10a 
SP 1902 
OP 1910 
DO 10.1101/gr.2722704 
UL http://genome.cshlp.org/content/14/10a/1902.abstract 
AB To derive a global perspective on the transcription of microRNAs (miRNAs) in mammals, we annotated the genomic position and context of this class of noncoding RNAs (ncRNAs) in the human and mouse genomes. Of the 232 known mammalian miRNAs, we found that 161 overlap with 123 defined transcription units (TUs). We identified miRNAs within introns of 90 protein-coding genes with a broad spectrum of molecular functions, and in both introns and exons of 66 mRNA-like noncoding RNAs (mlncRNAs). In addition, novel families of miRNAs based on host gene identity were identified. The transcription patterns of all miRNA host genes were curated from a variety of sources illustrating spatial, temporal, and physiological regulation of miRNA expression. These findings strongly suggest that miRNAs are transcribed in parallel with their host transcripts, and that the two different transcription classes of miRNAs (`exonic' and `intronic') identified here may require slightly different mechanisms of biogenesis.