Xiaojiang Chen

Professor

Molecular Biology
College of Letters Arts & Sciences

Research Topics

  • Cancer
  • Virology,
  • Immune defense
  • DNA/RNA enzymes
  • Protein Motors
  • Structural Biology

Research Overview

My research focuses on

1. Cancer biology, with emphasis on cell growth regulation through oncogenes, tumor suppressors, and DNA/RNA modifying enzymes (deaminases, helicases, polymerases);
2. Immune regulation (B, T cells) and host innate and acquired immune defenses against viruses (HIV, HPV, EBV).

Cancer, immune disorder (autoimmunity), and other human diseases can be caused by disruption of normal cellular processes, which can be resulted from somatic mutations, or be caused by viral infections (such as HPV, HCV, HIV). My laboratory studies the molecular mechanisms of the key cellular and viral proteins involved in oncogenesis and immune defenses.

In cancer biology, understanding cell growth control is critical for effective therapy for cancer and other related diseases. We study cell growth control from two angles;

1. how oncogenes regulate tumor suppressors (such as hDlg, p53, pRB, etc) to promote cell transformation.
2. how polymerase/primase and the ring-shaped helicases, which are efficient protein motors, control DNA replication and cell growth.

In immune defenses, APOBEC3G, a member of APOBEC deaminase family causing C-to-U mutation, is a potent innate immunity against HIV/HBV viruses. We study APOBEC3G and develop its anti-HIV activity as an anti-AIDS therapy. In the acquired immune defenses, we study both the initial antibody (humoral) response mediated via B-cell signaling and the subsequent antibody maturation through somatic hypermutation by another APOBEC deaminase, AID. We also study the T cell immune responses regulated by protein tyrosine phosphotases (PTP).

Our research tools include the powerful technology, X-ray crystallography, as well as functional biochemistry, molecular biology, cell biology, biophysics, and other biological methods.