The team is using functional genomic tools to study the nematode worm Caenorhabditis elegans (C. elegans), the first animal species whose genome was completely sequenced and a model organism to study how embryos develop. The study appearing in Current Biology was performed by NYU's Fabio Piano, an assistant professor, and Anita Fernandez, a post-doctoral researcher, at the Center for Comparative Functional Genomics.
Biologists can draw connections between genes based on systematically accumulated experimental evidence. Network diagrams that illustrate such connections show that most genes fall into highly interconnected groups called modules. These modules are often enriched for genes that share the same role. In order to determine the functions of genes whose role is unknown, researchers examine genes in the same module whose function has already been discovered. This approach has proven useful for learning about the roles of unknown genes.
Unlike most genes in the network, mel-28 had connections to two distinct modules. Piano and Fernandez tested the idea that mel-28 plays important roles in both chromosome segregation and nuclear envelope function. Part of this undertaking included examining the protein MEL-28, which the gene mel-28 encodes.
By fusing mel-28 to a gene-encoding GFP, a fluorescent marker, and expressing this fusion in early embryos, they visualized the movement of MEL-28 during cell division in living embryos. Consistent with the idea that MEL-28 had function in chromosome segregation and the nuclear envelope, the MEL-28-GFP fusion was observed to shuttle between the nuclear periphe ry and the chromosomes during cell division. Additional functional tests showed that mel-28 was essential to both the integrity of the nuclear envelope and to proper chromosome segregation. This study served as a validation of network modeling as a means to identify genes that coordinate multiple functions.