Micro RNAs encode 21-25 nt RNAs, which are generated
from a longer precursor. First discovered as the products of the C.
elegans heterochronic genes lin-4 and let-7 (see
CELL LINEAGE AND
CELL FATE), micro RNAs have very recently been found
to be widespread in biology, present in Drosophila, mammals,
plants and other organisms. The C. elegans genome encodes more
than 100 micro RNAs. Other than lin-4 and let-7, which
act to control developmental timing by inhibiting the translation
of the target mRNAs to which they bind, no micro RNA in any species
has been assigned any biological function. To explore the functions
of micro RNAs, we are collaborating with the laboratories of David
Bartel (Whitehead Institute, MIT) and Victor Ambros (Dartmouth) to
generate deletions in most and maybe all C. elegans micro RNA
genes. In addition, we are examining micro RNAs from mammals, with
a particular focus on those that function in the nervous system.
This Tecan robot is used for the construction
and screening of deletion libraries for various projects, including
our study of microRNAs.