Biology subjects

Masser, E. A.

Publications and source records attributed to Masser, E. A..

2 recordsLinked to original sources

bioRxiv2025

DUE-B Is Dispensable for Early Development and Genome Duplication in Vertebrates.

The DNA Unwinding Element-Binding protein (DUE-B) is a Cyclin Dependent Kinase (CDK) and Dbf4-Dependent Kinase (DDK) substrate that has been implicated in the control of DNA replication initiation. Previous studies reported that knocking down DUE-B in HeLa cells perturbs the G1-to-S phase transition, while depleting DUE-B from interphase Xenopus egg extracts impairs replication initiation. Based on these findings, the prevailing view is that DUE-B is a vertebrate-specific DNA replication initiation factor. Here, we asked whether due-b was an essential vertebrate gene in vivo, and whether it was critical for proper embryonic development in the zebrafish Danio rerio. We have generated due-b mutant zebrafish through genome-editing TALENs that fail to express due-b mRNA or protein. These mutant zebrafish are viable and survive to adulthood. They do not display outward developmental phenotypes, and when stressed with replication inhibitors, do not differ from their wild-type counterparts. Cell cycle analysis demonstrates that DNA replication occurs normally. Consistent with the zebrafish data, immunodepleting DUE-B from Xenopus nuclear egg extract did not impair DNA replication. Taken together, our findings indicate that DUE-B is dispensable for DNA replication and early development in vertebrates. SummaryThe DNA replication factor DUE-B is not required for zebrafish development or genome duplication, suggesting it plays a redundant or specialized role in DNA replication.

developmental biology↗

bioRxiv2022

Zebrafish Rif1 Impacts Zygotic Genome Activation, Replication Timing, and Sex Determination

Deregulated DNA replication causes human developmental disorders and cancer, but we know little about how DNA replication is coordinated with changes in transcription and chromatin structure. The initiation of replication forks follows a spatiotemporal pattern called the replication timing program. We have developed the zebrafish into a model system to study the mechanisms by which the replication timing program changes during the extensive changes in the cell cycle, transcription, chromatin organization, and nuclear structure that occur during development. Our previous studies identified changes in DNA replication timing patterns occurring from the onset of zygotic transcription through gastrulation in zebrafish embryos. Rif1 is required for DNA replication timing in a wide range of eukaryotes. The broader role of Rif1 in establishing the replication timing program and chromatin structure during early vertebrate development remains unknown. We have generated Rif1 mutant zebrafish and have performed RNA sequencing and whole-genome replication timing analyses on multiple developmental stages. Rif1 mutants were viable but had a defect in female sex determination. Surprisingly, Rif1 loss predominantly affected DNA replication timing after gastrulation, while its impacts on transcription were more substantial during zygotic genome activation. Our results indicate that Rif1 has distinct roles in DNA replication and transcription control that manifest at different stages of development.

cell biology↗