Book contents
- Frontmatter
- Contents
- List of contributors
- Foreword by Sidney Altman
- Foreword by Victor R. Ambros
- Introduction
- I Discovery of microRNAs in various organisms
- II MicroRNA functions and RNAi-mediated pathways
- III Computational biology of microRNAs
- IV Detection and quantitation of microRNAs
- V MicroRNAs in disease biology
- 22 Dysregulation of microRNAs in human malignancy
- 23 High throughput microRNAs profiling in cancers
- 24 Roles of microRNAs in cancer and development
- 25 miR-122 in mammalian liver
- 26 MiRNAs in glioblastoma
- 27 Role of microRNA pathway in Fragile X mental retardation
- 28 Insertion of miRNA125b-1 into immunoglobulin heavy chain gene locus mediated by V(D)J recombination in precursor B cell acute lymphoblastic leukemia
- 29 miRNAs in TPA-induced differentiation of HL-60 cells
- 30 MiRNAs in skeletal muscle differentiation
- 31 Identification and potential function of viral microRNAs
- 32 Lost in translation: regulation of HIV-1 by microRNAs and a key enzyme of RNA-directed RNA polymerase
- VI MicroRNAs in stem cell development
- Index
- Plate section
- References
25 - miR-122 in mammalian liver
from V - MicroRNAs in disease biology
Published online by Cambridge University Press: 22 August 2009
- Frontmatter
- Contents
- List of contributors
- Foreword by Sidney Altman
- Foreword by Victor R. Ambros
- Introduction
- I Discovery of microRNAs in various organisms
- II MicroRNA functions and RNAi-mediated pathways
- III Computational biology of microRNAs
- IV Detection and quantitation of microRNAs
- V MicroRNAs in disease biology
- 22 Dysregulation of microRNAs in human malignancy
- 23 High throughput microRNAs profiling in cancers
- 24 Roles of microRNAs in cancer and development
- 25 miR-122 in mammalian liver
- 26 MiRNAs in glioblastoma
- 27 Role of microRNA pathway in Fragile X mental retardation
- 28 Insertion of miRNA125b-1 into immunoglobulin heavy chain gene locus mediated by V(D)J recombination in precursor B cell acute lymphoblastic leukemia
- 29 miRNAs in TPA-induced differentiation of HL-60 cells
- 30 MiRNAs in skeletal muscle differentiation
- 31 Identification and potential function of viral microRNAs
- 32 Lost in translation: regulation of HIV-1 by microRNAs and a key enzyme of RNA-directed RNA polymerase
- VI MicroRNAs in stem cell development
- Index
- Plate section
- References
Summary
Introduction
MicroRNAs (miRNAs) are small non-coding RNA molecules about 22 nucleotides (nt) in length. They are derived by cleavage from larger precursor RNAs, most of which seem to be polyadenylated polymerase II transcripts (Lee et al., 2002). The processing of miRNA depends on two consecutive actions. The first is by the endonuclease drosha, which acts in the nucleus and cleaves the primary miRNA transcripts (pri-miRNAs) into ∼70–80 nt hairpin-like miRNA precursors (pre-miRNAs)(Lee et al., 2003). This miRNA precursor is then transported to the cytoplasm (Bohnsack et al., 2004; Lund et al., 2004) where it is further cleaved by the nuclease dicer, to release the mature miRNA species (Ketting et al., 2001; Lee et al., 2003). These miRNAs can then regulate the expression of target genes with complementary sequence by either cleavage of the target mRNA or inhibition of the translation (Bartel, 2004).
In mammals, hundreds of miRNAs have been identified, some of which are expressed in tissue-specific (Lagos-Quintana et al., 2002) and developmental stage-specific manner (Krichevsky et al., 2003). Altered expression of specific miRNA genes has been associated with the development of cancers (McManus, 2003; see also Chapter 23 in this book). miR-122 is a liver-specific miRNA and in a recent study we examined the expression of miR-122 during mouse liver development and in liver tumors (Chang et al., 2004).
- Type
- Chapter
- Information
- MicroRNAsFrom Basic Science to Disease Biology, pp. 338 - 349Publisher: Cambridge University PressPrint publication year: 2007