Disease relevance of UL21

• The UL21 gene products of herpes simplex virus 1 are dispensable for growth in cultured cells [1].
• (i) The replication of delta UL21 was identical to that of the parent herpes simplex virus 1 (HSV-1) strain F in Vero cells, but the yields were three- to fivefold lower than those of the parent virus in human embryonic lung cells [1].
• We determined 3,135 bp of the nucleotide sequence located in an 8.5 kb EcoRI-E fragment in the unique long (UL) genome region of Marek's disease virus serotype 2 (MDV2), and identified UL20 and UL21 homologous genes of herpes simplex virus type 1 (HSV-1) [2].
• The putative protein product of the MDV2 UL20 gene had a relatively low homology but that of the MDV2 UL21 gene had a moderate homology among herpesviruses [2].
• Deletion of the UL21 gene in Pseudorabies virus results in the formation of DNA-deprived capsids: an electron microscopy study [3].

High impact information on UL21

• A viral deletion mutant (delta UL21) that lacked the sequences encoding 484 of the predicted first 535 amino acids of the UL21 open reading frame was genetically engineered and studied with respect to its phenotype in cells in culture [1].
• (iii) Immunofluorescence studies localized the UL21 antigen primarily in brightly staining granules in the cytoplasms of infected cells [1].
• (ii) To characterize the UL21 protein, we immunized rabbits against a purified bacterial fusion protein consisting of glutathione S-transferase fused to the majority of the coding domain of the UL21 gene [1].
• Vero cell lines have been isolated that are transformed with either the BglII N (UL19) or EcoRI G (UL16 to UL21) fragment of KOS [4].
• RESULTS: We found that the HSV-1 UL21 gene product, a capsid-associated tegument protein with an apparent molecular mass of 62 kDa, promotes the outgrowth of long cellular processes when it is over-expressed in non-neural cells [5].

Biological context of UL21

• In addition, an open reading frame (MDV2 ORF 273), which has been identified within the UL21 homologous gene of MDV2, has no apparent relation to any other known herpesvirus genes [2].
• Identification and DNA sequence analysis of the Marek's disease virus serotype 2 genes homologous to the herpes simplex virus type 1 UL20 and UL21 [2].
• We studied the morphogenesis of three pseudorabies virus mutants lacking parts of the gene homologous to the UL21 gene of the herpes simplex virus type 1 [3].
• Although on SK-6 cells and PLAM, the virus-assembly and egress of mutant virus M155, lacking almost the entire UL21 gene, was similar to that of the rescued PRV mutant, M155 producing virions containing little or no DNA (A-type particles) [3].

Anatomical context of UL21

• The UL21 protein co-localizes and physically associates with microtubules in the long processes [5].

Analytical, diagnostic and therapeutic context of UL21

• Northern blot analysis and reverse transcriptase polymerase chain reaction confirmed the existance of RNA transcripts related to the UL20 and ORF 273 genes in MDV2-infected cells, except no transcript related to the UL21 gene being detected [2].

References