Recombinant Rat Uncharacterized protein C17orf53 homolog

Introduction

Recombinant Rat Uncharacterized Protein C17orf53 Homolog is a laboratory-engineered version of the rat ortholog of human C17orf53, a gene encoding a protein critical for DNA replication and interstrand crosslink (ICL) repair. While direct studies on the rat homolog remain limited, insights from human and vertebrate models reveal its conserved role in genome maintenance . This article synthesizes structural, functional, and mechanistic data from diverse sources to contextualize its biological significance.

Protein Isoforms

The human C17orf53 gene produces four major isoforms, which inform predictions for its rat homolog:

Data adapted from human studies .

Domain Architecture

• DUF4539: A domain of unknown function with a predicted OB-fold for ssDNA binding .

• PRR18: Proline-rich region implicated in protein-protein interactions .

• Nuclear Localization Signals (NLS): Directs nuclear localization, critical for DNA repair functions .

Post-Translational Modifications

• Phosphorylation: Multiple predicted sites suggest regulatory roles .

• Glycosylation: O-linked glycosylation observed near the PRR18 domain .

Interstrand Crosslink (ICL) Repair

• Mechanism: C17orf53 operates downstream of the Fanconi Anemia (FA) pathway, facilitating homologous recombination (HR) by promoting RAD51-mediated repair .

• Key Interactions:

  • MCM8/9 Helicase: Enhances helicase activity to unwind DNA at stalled replication forks .

  • RPA1: Binds replication protein A (RPA) to stabilize ssDNA during repair .

DNA Replication

• Loss of C17orf53 reduces replication fork speed by ~30%, as shown by DNA fiber assays .

• CRISPR screens link C17orf53 depletion to hypersensitivity to ATR inhibitors, underscoring its role in replication stress response .

Genetic and Omics Insights

• CRISPR Screens: C17orf53 knockout (KO) cells exhibit synthetic lethality with FA/HR pathway defects, indicating functional overlap .

• Expression Profiles:

  • Elevated in cancers (e.g., lymphomas, gliomas) and proliferating tissues (testis, heart) .

  • Correlates with poor prognosis in TCGA cancer datasets .

Biochemical Properties

• ssDNA Binding: The DUF4539 domain binds ssDNA with high affinity ($K_d = 12 \pm 3 \, \text{nM}$) .

• Helicase Activation: MCM8IP (C17orf53) increases MCM8-9 helicase processivity by 2.5-fold .

Recombinant Applications

While no direct studies on recombinant rat C17orf53 exist, human recombinant variants are used to:

1. Study ICL repair mechanisms in vitro .

2. Investigate replication stress responses via siRNA/CRISPR-complementary assays .

3. Develop biomarkers for cancer progression .

Evolutionary Conservation

• Orthologs: Found exclusively in vertebrates, with 85% sequence identity between human and rat .

• Divergence: Evolved ~1.6 billion years ago, suggesting ancestral roles in genome maintenance .

Challenges and Future Directions

• Functional Redundancy: Overlap with MCM8/9 complicates mechanistic studies .

• Therapeutic Potential: High expression in cancers positions C17orf53 as a candidate target for ATR/CHK1 inhibitor therapies .