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9.B.410. The Viral E3 CR1 (E3-CR1) Family

The proteins of this family are found in a variety of eukaryotic viruses and in general, have an N-terminal TMS, probably the leader sequence that directs the nascent polypoptide chain to the membrane, and a large C-terminal TMS. The E3 region of all simian and human type viruses, classified within species of human mastadenovirus B (HAdV-B) encodes two unique highly conserved ORFs of unknown function designated E3-CR1beta and E3-CR1gamma. Lakshmi Narayan and Kajon 2020 generated a HAdV-3 mutant encoding small epitope tags at the N-termini of both E3-CR1beta and E3-CR1gamma (HAdV-3 N-tag wt) and a double knock out (HAdV-3 N-tag DKO) mutant virus that does not express either protein. Our studies show that HAdV-3 E3-CR1beta and E3-CR1gamma are type I transmembrane proteins that are produced predominantly at late times post infection, are glycosylated, co-localize at the plasma membrane of non-polarized epithelial cells, and interact with each other. At their extreme C-termini HAdV-B E3-CR1beta and E3-CR1gamma possess a conserved di-leucine motif followed by a class II PDZ domain binding motif (PBM). HAdV-3 E3-CR1beta and E3-CR1gamma are dispensable for virus growth, progeny release, spread, and plaque formation in A549 cells (Lakshmi Narayan and Kajon 2020).


References associated with 9.B.410 family:

Engel, P., N. Pérez-Carmona, M.M. Albà, K. Robertson, P. Ghazal, and A. Angulo. (2011). Human cytomegalovirus UL7, a homologue of the SLAM-family receptor CD229, impairs cytokine production. Immunol Cell Biol 89: 753-766. 21670740
Lakshmi Narayan, P.K. and A.E. Kajon. (2020). Human mastadenovirus-B (HAdV-B)-specific E3-CR1β and E3-CR1γ glycoproteins interact with each other and localize at the plasma membrane of non-polarized airway epithelial cells. Virology 546: 67-78. 32452418