High throughput approaches reveal splicing of primary microRNA transcripts and tissue specific expression of mature microRNAs in Vitis vinifera.
BACKGROUND
MicroRNAs are short (approximately 21 base) single stranded RNAs that, in plants, are generally coded by specific genes and cleaved specifically from hairpin precursors. MicroRNAs are critical for the regulation of multiple developmental, stress related and other physiological processes in plants. The recent annotation of the genome of the grapevine (Vitis vinifera L.) allowed the identification of many putative conserved microRNA precursors, grouped into multiple gene families.


RESULTS
Here we use oligonucleotide arrays to provide the first indication that many of these microRNAs show differential expression patterns between tissues and during the maturation of fruit in the grapevine. Furthermore we demonstrate that whole transcriptome sequencing and deep-sequencing of small RNA fractions can be used both to identify which microRNA precursors are expressed in different tissues and to estimate genomic coordinates and patterns of splicing and alternative splicing for many primary miRNA transcripts.


CONCLUSIONS
Our results show that many microRNAs are differentially expressed in different tissues and during fruit maturation in the grapevine. Furthermore, the demonstration that whole transcriptome sequencing can be used to identify candidate splicing events and approximate primary microRNA transcript coordinates represents a significant step towards the large-scale elucidation of mechanisms regulating the expression of microRNAs at the transcriptional and post-transcriptional levels.
Mica
Erica
E
Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy. erica.mica@sssup.it
Piccolo
Viviana
V
Delledonne
Massimo
M
Ferrarini
Alberto
A
Pezzotti
Mario
M
Casati
Cesare
C
Del Fabbro
Cristian
C
Valle
Giorgio
G
Policriti
Alberto
A
Morgante
Michele
M
Pesole
Graziano
G
Pè
M Enrico
ME
Horner
David S
DS
D017398:Alternative Splicing; D001483:Base Sequence; D019295:Computational Biology; D005638:Fruit / Q000235:genetics; D020869:Gene Expression Profiling; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D020411:Oligonucleotide Array Sequence Analysis; D012326:RNA Splicing; D018749:RNA, Plant / Q000235:genetics; D017423:Sequence Analysis, RNA; D027843:Vitis / Q000235:genetics*
D035683:MicroRNAs; D018749:RNA, Plant