Hepatitis B virus X open reading frame mRNA transcript (HBx mRNA)

The Hepatitis B virus X (HBx) open reading frame mRNA transcript encodes the HBx protein, a 154-amino acid regulatory protein that is indispensable for the Hepatitis B virus (HBV) life cycle (Source: UniProt P03401). HBx serves as a pleiotropic transactivator, enhancing the transcription of viral genes and modulating host signaling pathways such as NF-kappaB and MAPK to create an environment conducive to viral persistence (Source: PubMed PMID: 26011025). It is particularly critical for the establishment and epigenetic regulation of the covalently closed circular DNA (cccDNA) minichromosome, which acts as the template for all viral transcripts (Source: PubMed PMID: 27050319). Beyond its role in replication, HBx is a recognized oncoprotein that contributes to the pathogenesis of hepatocellular carcinoma (HCC) by inducing oxidative stress and interfering with host DNA repair mechanisms (Source: PubMed PMID: 24507440). Because the HBV genome is highly compact with overlapping reading frames, therapeutic targeting of the HBx mRNA transcript using RNA interference (RNAi) or antisense oligonucleotides (ASOs) can simultaneously reduce the expression of multiple viral antigens, including HBsAg. This multi-pronged silencing approach is a primary strategy in current clinical trials aimed at achieving a functional cure for chronic hepatitis B (Source: PubMed PMID: 33161334).

Other names

HBV X mRNAHepatitis B virus X gene transcriptHBx transcriptHBV X-protein mRNA

Therapeutic agents target the HBx mRNA transcript through RNA interference (RNAi) or antisense oligonucleotide (ASO) mechanisms. RNAi-based drugs (siRNAs) utilize the RNA-induced silencing complex (RISC) to catalyze the sequence-specific cleavage of the mRNA, while ASOs bind to the transcript to form a DNA-RNA hybrid that is degraded by RNase H, effectively silencing the production of the HBx protein and other overlapping viral proteins (Source: PubMed PMID: 31536357, 33161334).