Welcome to the collaborations section.

The ins project

The collaboration with Prof. MM Green lead to the isolation and cytogenetic characterization of the mutation inseparabile which generates in males a high frequency of A-X females. The mutation, segregating in low frequency in a laboratory stock, maps to cytological location 82F7-11 in the third chromosome. The mutation acts premeiotically in the male germ line. Disrupting the X chromosome centromeric heterochromatin suppresses the formation of A-X chromosome, implying that the mutation is involved in chromatid cohesion. The inseparabile mutation also affects disjunction of the chromosome 4 in males. It is possible that the mutation was responsible for the original A-X female found by L. V. Morgan in 1921. (the image on the left is an original picture of RP obtained during this study at Davis - please do not reproduce without explicit permission)

Reference

Green M.M. and R. Piergentili (2000)
On the origin of metacentric, attached-X chromosomes in Drosophila melanogaster males.
Proc. Natl. Acad. Sci. USA 97(26):14484-14487

The RNAi project

RNAi screens have identified many genes required for mitotic cell division of Drosophila tissue culture cells. However, the inventory of such genes is still incomplete. In this project the powers of bioinformatics and the RNAi technology have been combined to detect novel mitotic genes. It has been found that Drosophila genes involved in mitosis tend to be transcriptionally coexpressed. Thus, a coexpression-based list of 1000 genes highly enriched in mitotic functions has been constructed. RNAi to each of these genes was performed and dsRNA-treated cells were examined for both chromosome structure and spindle organization. This analysis allowed the identification of 142 mitotic genes, which have been grouped in 16 phenoclusters. 71 of theses genes have not been characterized previously; 40 of them are required for chromosome integrity and 31 for spindle assembly and/or chromosome segregation. Interestingly, RNAi to genes encoding kinetochore components or highly conserved splicing factors resulted in identical phenotypes, highlighting a role of splicing factors in centromere function.

Reference

Somma M. P., Ceprani F., Bucciarelli E., Naim V., De Arcangelis V., Piergentili R., Palena A., Ciapponi L., Giansanti M. G., Pellacani C., Petrucci R., Cenci G., Vernì F., Fasulo B., Goldberg M. L., Di Cunto F. and Gatti M. (2008)
Identification of Drosophila mitotic genes by combining co-expression analysis and RNA interference.
PLoS Genetics 4(7):e1000126