Boese QF et al. (1998) East Coast Worm Meeting "Mapping and Cloning the mut-2 Mutator"

Collins JJ, Pelliccia JG, Alcazar R, Boese QF

[East Coast Worm Meeting, 1998]

We are interested in the function of mut-2, a gene that regulates the movement of all known transposons in the genome of Caenorhabditis elegans. Our goal is to map, clone and characterize this interesting and elusive gene. We have mapped mut-2 to a 0.24 map unit region of Linkage Group 1 flanked by dpy-14 and sem-4 . This interval corresponds to a physical distance of about 200-300 kilobases that has complete cosmid/YAC coverage and for which complete sequence is available. However, the phenotypes conferred by mut-2(r459) -- enhanced germ-line transposition (Mut) and a high incidence of males (Him) -- preclude straightforward rescue approaches for identifying a molecular clone of the gene. To circumvent this obstacle, we are searching the mut-2 interval for Bristol/Bergerac polymorphisms to use in higher resolution mapping of the gene. We are also searching the finished sequence of the region for candidate genes to examine. Understanding how mut-2 functions will enhance our understanding of the mechanisms that control transposition in eukaryotic genomes. It should also provide better ways to manipulate transposon activity in C. elegans, facilitating reverse genetic approaches in this important model organism. This work is supported by several Grants-in-aid of Research from Sigma Xi, the Scientific Research Society and the Graduate School of UNH.

Wright, Ashley et al. (2013) International Worm Meeting "Determining Fragile Nucleosome Distribution Bias Within the Chromosome."

Wright, Ashley, Johnson, Steven

[International Worm Meeting, 2013]

Nucleosomes are the fundamental units of chromatin compaction and play a major role in many molecular phenomena including gene regulation. We recently published an analysis comparing nucleosome occupancy between in vivo isolated nucleosomes and in vitro nucleosome reconstitutions on C. elegans genomic DNA1. This analysis revealed nucleosome depletion on the arms of worm chromosomes in vivo. This result can be explained by two possibilities. Either the ends of chromosomes, in general, have a lower frequency of nucleosomes or this distribution may be the result of a higher frequency of nucleosomes sensitive to Micrococcal nuclease digestion (Fragile Nucleosomes2) localized to the chromosome ends. In order to understand the cause of this nucleosome depletion we are doing experiments to establish if fragile nucleosomes are unevenly distributed and depleted towards the chromosome ends. Therefore, we have isolated mononucleosome cores from a series of Micrococcal nuclease digestions of increasing concentration and digestion time. Extensive Sanger sequencing has been performed to confirm the integrity and diversity of our nucleosome core library. Our current efforts are concentrating on high-throughput sequencing of our cores and genomic analysis. Upon successful completion of sequencing, we will map the reads back to the worm genome in order to determine the overall distribution of each digestion condition. The result can then be correlated to our in vivo data. An uneven distribution of the lightly digested cores, favoring the ends would suggest the general presence of fragile nucleosomes. At the end of this investigation, we hope to continue to push forward our understanding of the global positions of nucleosomes and their effect on cellular processes. 1Locke, G. et al. (2013) Global remodeling of nucleosome positions in C. elegans. BMC Genomics. 2 Xi, Y. et al. (2011) Nucleosome fragility reveals novel functional states of chromatin and poises genes for activation. Genome Res. 21 (5):718-724.