It's about time: an investigation into the role of abnormal oocyte (abo) in embryonic histone gene regulation
Authors: Eric Albanese; Casey Schmidt; Leila Rieder
Affiliation: Emory University
Keywords: d. repressors/corepressors; k. nuclear organization
Abnormal oocyte (abo) is a maternal effect gene first characterized by Larry Sandler in 1970. Loss-of-function mutations in abo cause defects in embryonic development. Later characterization of abo revealed that it negatively regulates histone gene expression—likely through targeting histone promoters. Interestingly, the viability defects prompted by abo mutation can be rescued by an overexpression of heterochromatic regions, suggesting that heterochromatin can act as a “sponge” to soak up the excess histones. Despite these important experiments, abo has received little attention since the early 2000s, and its precise role in histone repression is unknown. Thus, our goal is to define the molecular role of abo in histone gene expression. To that end, we generated V5-tagged abo lines via CRISPR. Using these lines, we probe abo localization through staining polytene chromosomes and determine abo expression levels by western blot. We also utilize available abo mutants and RNAi lines to determine the molecular mechanism of histone gene repression. Overall, our work will contribute to a growing body of knowledge regarding histone gene regulation in early embryo development.