Program of the 2001 International Worm Meeting - Sternberg Lab ...

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separate pathways. Since some evidence of
meiotic nuclei still exists in the triple mutant, a
possible fourth pathway could be involved.
65. Roles and modes of action of
rad-51
Cinzia Rinaldo 1 , Paolo
Bazzicalupo 1 , Sara Ederle 2 ,
Massimo Hilliard 1 , Adriana La
Volpe 1,3
1 International Institute of Genetics and
Biophysics -CNR- 10, Via Marconi 80125
Naples, Italy
2 Dipartimento di Genetica e Biologia Generale
e Molecolare, Facoltà di Scienze, Universita’
di Napoli "Federico II", 8, Via Mezzocannone
- 80134 Naples, Italy
3 lavolpe@iigbna.iigb.na.cnr.it
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Our understanding of genetic control of meiotic
recombination comes from studies in the
unicellular eukaryote Saccharomyces cerevisiae.
Most gene involved in control of recombination
and meiosis are conserved throughout evolution.
However, metazoa have developed a germ cell
line distinct from the somatic cell line requiring
a different kind of regulation compared to
unicellular eukaryotes. Furthermore, in distant
species, in spite of evolutionary conservation,
similar genes may be subject to different
regulation and interactions. Accordingly,
elimination of a conserved molecule or
interference with a conserved pathway may lead
to quite different results in different organisms.
For this reason, genetic and biochemical studies
in different organisms are likely to contribute to
an understanding of the crucial features and
fundamental components of recombination
pathways and their evolution.
Among eukaryotes, C. elegans is the only
organism known so far provided with a single
recA like gene, the homolog of RAD51.
Surprisingly, the meiosis specific DMC1 gene
present in fungi, plants and mammals, is absent
in C. elegans. RNA interference of the rad-51
gene in C. elegans leads to a number of visible
phenotypes such as i) high levels of embryonic
lethality, ii) increase in the frequency of males,
iii) reduced fertility, and iv) hypersensitivity to
ionizing radiation in soma. We have analysed in
details the mechanisms leading to the above
described phenotypes, in order to understand the
different functions and modes of action of
rad-51 in somatic and germ line cells.
We demonstrated that this gene is required
at several steps of gametogenesis: gene