EAP, a highly conserved cellular protein associated with Epstein-Barr virus small RNAs (EBERs)

Area of Science:

• Molecular Virology
• RNA Biology
• Protein Biochemistry

Background:

• Human B lymphocytes infected with Epstein-Barr virus (EBV) produce large quantities of Epstein-Barr encoded RNAs (EBERs).
• EBERs are small nuclear RNAs of unknown function, known to bind the La autoantigen, a common feature of RNA polymerase III transcripts.

Purpose of the Study:

• To identify and characterize host-encoded proteins that associate with EBERs.
• To investigate the function and properties of the newly identified EBER-associated protein (EAP).

Main Methods:

• Purification of EAP using a devised procedure.
• Cloning of EAP cDNA from a human placental cDNA library.
• Amino acid sequence analysis and comparison with known proteins using polymerase chain reaction (PCR) data.

Main Results:

• Discovery of EAP, a small polypeptide (14,777 daltons, 128 amino acids) that binds both EBER 1 and EBER 2.
• EAP is also found associated with analogous viral RNAs in baboon cells infected with herpesvirus papio (HVP).
• EAP's predicted amino acid sequence shows 77% identity to a sea urchin protein (217), containing a potential nuclear localization signal and acidic C-terminus.

Conclusions:

• EAP is a novel, highly abundant host protein that binds to EBV-encoded RNAs (EBERs).
• The structural similarity of EAP to a developmentally regulated sea urchin protein suggests potential roles in cellular processes beyond viral RNA binding.
• Further research is needed to elucidate the precise function of EAP and its significance in EBV-infected cells and potentially other biological systems.