Lin-4 was the first miRNA discovered in 1993 in C. elegans by Victor Ambros. miRNAs are non-coding endogenous RNAs that regulate gene expression by directing target mRNAs for degradation or translational repression. They form stem-loop or hairpin structures through internal sequence complementarity in single-stranded RNA which allows for folding. Several examples of miRNAs and their target genes in nematodes, humans, insects, and plants are provided, demonstrating roles in processes like physiological timing, immune system development, apoptosis, growth control, and leaf development.
2. • mi RNAs are non-coding endogenous RNAs
that regulate gene expressions by directing
their target mrna for degradation or
translational repression
• Discovered by- Victor Ambros(1993).
Discovered in – Caenorhabditis elegans(lin-4).
3. • The structure of miRNA are formed by the internal sequence
complimentatory in single stranded RNA which results in the
folding of ssRNA and leads to form a stemloop or hair pin like
structures.
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7. miRNA Target gene(s) Biological functions
Nematodes
Lin-4
Lin-14 Physiological condition and
developmental timing
H.Sapiens
miR-146
C-myc,ROCK1 Development and function of
immune system.
Insects
Bantam miRNA
DM-hid apoptotic
protein
Apoptosis and growth control
during development.
Plants
miR-jaw
Tcp-4 Leaf developement
Mir 159 myb33 Leaf developement
