Abstract: Evolutionarily distant organisms have not only orthologs, but also
nonhomologous proteins that build functionally similar subcellular structures.
For instance, this is true with protein components of the synaptonemal complex
(SC), a universal ultrastructure that ensures the successful pairing and
recombination of homologous chromosomes during meiosis. We aimed at developing
a method to search databases for genes that code for such nonhomologous but
functionally analogous proteins. Advantage was taken of the ultrastructural
parameters of SC and the conformation of SC proteins responsible for these.
Proteins involved in SC central space are known to be similar in secondary
structure. Using published data, we found a highly significant correlation
between the width of the SC central space and the length of rod-shaped central
domain of mammalian and yeast intermediate proteins forming transversal
filaments in the SC central space. Basing on this, we suggested a method for
searching genome databases of distant organisms for genes whose virtual
proteins meet the above correlation requirement. Our recent finding of the
Drosophila melanogaster CG17604 gene coding for synaptonemal complex
transversal filament protein received experimental support from another lab.
With the same strategy, we showed that the Arabidopsis thaliana and
Caenorhabditis elegans genomes contain unique genes coding for such
proteins.
