Drosophila Ctf4 is essential for efficient DNA replication and normal cell cycle progression.

DNA replication coordination is essential for genome stability. The Ctf4 protein connects MCM helicase and DNA polymerase α primase at replication forks. It is part of the Fork Protection Complex and aids sister chromatid cohesion. Prior research has shown Ctf4's role in yeast and human cells. However, its function in multicellular organisms remains unclear. This gap motivated the study of Ctf4 in Drosophila. No prior work had resolved how Ctf4 contributes to replication in a whole organism. The study aims to bridge this gap. Understanding Ctf4's role could clarify its involvement in development and disease.

The study aimed to determine Ctf4's role in Drosophila DNA replication. The researchers focused on whether Ctf4 is essential for S phase progression. They wanted to test if Ctf4 supports sister chromatid cohesion in vivo. The motivation came from gaps in understanding Ctf4's conservation across species. The study also sought to establish Drosophila as a model for Ctf4 research. RNAi knockdown was used to assess Ctf4's function. The authors proposed that Drosophila could reveal Ctf4's developmental roles. This approach allows for in vivo functional analysis.

The researchers used RNAi to knock down CTF4 in Drosophila. They assessed viability and S phase progression in affected cells. Sister chromatid cohesion was evaluated using cytological methods. Endoreplication and replication stress responses were also measured. The interaction of Ctf4 with GINS complex and Mcm2 was tested. Polymerase α primase binding was analyzed in vivo. The study compared findings to prior work in yeast and human cells. These methods allowed a comprehensive view of Ctf4's function.

RNAi knockdown of CTF4 caused reduced viability in Drosophila. S phase progression was significantly impaired in affected cells. Sister chromatid cohesion was disrupted in Ctf4-deficient cells. Endoreplication was also affected by Ctf4 depletion. Replication stress tolerance decreased in the absence of Ctf4. Ctf4 interacted with GINS complex and Mcm2 proteins in vivo. Polymerase α primase binding was confirmed as a Ctf4 function. These findings align with prior reports in yeast and human cells.

The study shows Ctf4 is essential for DNA replication in Drosophila. S phase progression and sister chromatid cohesion depend on Ctf4. The protein's role in endoreplication and replication stress is confirmed. Ctf4 interacts with GINS and Mcm2 as previously reported. Findings are consistent with Ctf4's known function in other species. Drosophila is a valid model for further Ctf4 research. The authors propose that Ctf4's role is conserved across eukaryotes. These results support the importance of Ctf4 in replication fork stability.