We have cloned and characterized a single copy C. reinhardtii gene containing an open reading frame of 333 nucleotides encoding a 12.7 kDa protein. The novel protein, DIP13, exhibits 60% identity with two mammalian proteins, human NA14 and an unnamed mouse protein. Homologous sequences are also present in several protozoan, trematode and fish genomes, but no homologs have been found in the completed genomes of yeast, Drosophila, C. elegans and A. thaliana. By using a specific antibody we have localized DIP13 to microtubule structures, namely basal bodies, flagellar axonemes and cytoplasmic microtubules. Anti-DIP13 antibody also specifically recognized human NA14 by immunofluorescence and stained basal bodies and flagella of human sperm cells as well as the centrosome of HeLa cells. Expression of the DIP13 open reading frame in antisense orientation in Chlamydomonas resulted in multinucleate, multiflagellate cells,which suggests a role for this protein in ensuring proper cell division. Thus,DIP13/NA14 could represent the founding members of a new class of highly conserved proteins that are associated with microtubule structures.

HLA phenotyping is needed in a larger number of SCFE twin cases to evaluate phenotypic patterns for coincidence to provide a basis for the genetic expression of this condition.

In how far there exists a significant correlation between the newly identified triple polymorphism in the Tau gene and an alternated risk for FTD must be evaluated in a lager population. The proximity of these polymorphisms to the exon-intron border would facilitate functional influences on gene expression patterns. These preliminary results described, above potentially point to further pathogenetic factors in the genesis of FTD.