There are four known genes encoded by the genome, called C, X, P, and S. The core protein is coded for by gene C (HBcAg), and its start codon is preceded by an upstream in-frame AUG start codon from which the pre-core protein is produced. HBeAg is produced by proteolytic processing of the pre-core protein. In some rare strains of the virus known as Hepatitis B virus precore mutants, no HBeAg is present. The DNA polymerase is encoded by gene P. Gene S is the gene that codes for the surface antigen (HBsAg). The HBsAg gene is one long open reading frame but contains three in frame "start" (ATG) codons that divide the gene into three sections, pre-S1, pre-S2, and S. Because of the multiple start codons, polypeptides of three different sizes called large (the order from surface to the inside: pre-S1, pre-S2, and S ), middle (pre-S2, S), and small (S) are produced. There is a myristyl group, which plays an important role in infection, on the amino-terminal end of the preS1 part of the large (L) protein. In addition to that, N terminus of the L protein have virus attachment and capsid binding sites. Because of that, the N termini of half of the L protein molecules are positioned outside the membrane and the other half positioned inside the membrane.The function of the protein coded for by gene X is not fully understood but it is associated with the development of liver cancer.
Transient lingual papillitis  are painful, hypertrophic, red and white lingual papillae on the tongue. Cause
Transient lingual papillitis can affect males and females as early as 3 years of age. In many cases, the cause is unknown. Some dental professionals believe the inflammation is due to chronic irritation from teeth, fillings, or dental appliances. Stress, poor nutrition, smoking, and alcohol use may also be initiating factors. == References ==