Differences in vertebrate microRNA expression.
MicroRNAs (miRNAs) attenuate gene expression by means of translational inhibition and mRNA degradation. They are abundant, highly conserved, and predicted to regulate a large number of transcripts. Several hundred miRNA classes are known, and many are associated with cell proliferation and differentiation. Many exhibit tissue-specific expression, which aids in evaluating their functions, and it has been assumed that their high level of sequence conservation implies a high level of expression conservation. A limited amount of data supports this, although discrepancies do exist. By comparing the expression of approximately 100 miRNAs in medaka and chicken with existing data for zebrafish and mouse, we conclude that the timing and location of miRNA expression is not strictly conserved. In some instances, differences in expression are associated with changes in miRNA copy number, genomic context, or both between species. Variation in miRNA expression is more pronounced the greater the differences in physiology, and it is enticing to speculate that changes in miRNA expression may play a role in shaping the physiological differences produced during animal development.
Ason
Brandon
B
Hubrecht Laboratory, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.
Darnell
Diana K
DK
Wittbrodt
Beate
B
Berezikov
Eugene
E
Kloosterman
Wigard P
WP
Wittbrodt
Jochen
J
Antin
Parker B
PB
Plasterk
Ronald H A
RH
D000818:Animals; D002645:Chickens / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D009990:Oryzias / Q000196:embryology / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014714:Vertebrates / Q000235:genetics*; D015027:Zebrafish / Q000196:embryology / Q000235:genetics
D035683:MicroRNAs; D012333:RNA, Messenger