# Non-canonical chimeric proteins generated during Adenovirus infection

> **NIH NIH R21** · CHILDREN'S HOSP OF PHILADELPHIA · 2021 · $220,000

## Abstract

PROJECT SUMMARY
Adenovirus (AdV) and other human DNA viruses with limited genome size have maximized gene expression
and coding potential through the use of alternative splicing and polyadenylation. The AdV double-stranded
DNA genome has served as a powerful system for seminal discoveries in gene regulation and RNA
processing. There are five early transcription units (E1A, E1B, E2, E3 and E4) which are transcribed by host
RNA polymerase II and processed by cellular machinery. Each viral transcription unit is driven by a designated
promoter and gives rise to multiple mRNAs generated by alternative splicing. The canonical proteins produced
from each viral transcript have been assigned functions through the study of infection with viral mutants. The
E2 region encodes three proteins involved in viral DNA replication. The E4 region encodes multifunctional
proteins involved in regulation of transcription, splicing and translation of viral mRNAs, as well as antagonizing
intrinsic cellular defenses. We combined short-read and direct long-read sequencing technologies to define
viral transcripts during AdV infection, and thus generated the most complete annotation of the virus
transcriptome. Our analysis identified a number of non-canonical chimeric proteins that fuse polypeptides from
different early transcriptional units. Here we focus on one of these unexpected gene products that we have
designated E4orf6/DBP since it spans the E2 and E4 regions. Our preliminary data show that this novel
chimeric protein is robustly expressed, and we propose that it could provide a yet unidentified function during
AdV infection. In Aim 1 we will evaluate how the transcript is generated, and the importance of its interacting
partners. In Aim 2 we will determine functions of the fusion protein, and its impact on infection. We have
generated or accumulated all reagents and technical expertise necessary to define the functions of the
E4orf6/DBP chimeric protein. Our findings challenge the concept of discrete early transcriptional units with
their own designated promoter and poly(A) site, and suggest that studying individual open reading frames may
not reflect the true complexity of the viral transcriptome. Our studies aim to uncover molecular mechanisms
that regulate virus-host interactions by providing a deeper understanding of non-canonical fusion proteins that
expand the diversity of the viral proteome. The proposal will generate a model approach for interrogating
functions of non-canonical chimeric proteins generated by viruses with complex viral proteomes.

## Key facts

- **NIH application ID:** 10312411
- **Project number:** 1R21AI154654-01A1
- **Recipient organization:** CHILDREN'S HOSP OF PHILADELPHIA
- **Principal Investigator:** Matthew D. Weitzman
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $220,000
- **Award type:** 1
- **Project period:** 2021-07-09 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10312411

## Citation

> US National Institutes of Health, RePORTER application 10312411, Non-canonical chimeric proteins generated during Adenovirus infection (1R21AI154654-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10312411. Licensed CC0.

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