[Source: US National Library of Medicine, full text: (LINK). Abstract, edited.]
J Virol. 2013 May 29. [Epub ahead of print]

Genetic characterization of Betacoronavirus lineage C viruses in bats revealed marked sequence divergence in the spike protein of Pipistrellus bat coronavirus HKU5 in Japanese pipistrelle: implications on the origin of the novel Middle East Respiratory Syndrome Coronavirus.

Lau SK, Li KS, Tsang AK, Lam CS, Ahmed S, Chen H, Chan KH, Woo PC, Yuen KY.

Source: State Key Laboratory of Emerging Infectious Diseases.


While the novel Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is closely related to Tylonycteris bat CoV HKU4 (Ty-BatCoV HKU4) and Pipistrellus bat CoV HKU5 (Pi-BatCoV HKU5) in bats from Hong Kong, and other potential lineage C betacoronaviruses in bats from Africa, Europe and America, its animal origin remains obscure. To better understand the role of bats in its origin, we examined the molecular epidemiology and evolution of lineage C betacoronaviruses among bats. Ty-BatCoV HKU4 and Pi-BatCoV HKU5 were detected in 29% and 25% of alimentary samples from lesser bamboo bat (Tylonycteris pachypus) and Japanese pipistrelle (Pipistrellus abramus) respectively. Sequencing of their RdRp, S and N genes revealed that MERS-CoV is more closely related to Pi-BatCoV HKU5 in RdRp (92.1-92.3% aa identities) but to Ty-BatCoV HKU4 in S (66.8-67.4% aa identities) and N (71.9-72.3% aa identities). Although both viruses were under purifying selection, the S of Pi-BatCoV HKU5 displayed marked sequence polymorphisms and more positively selected sites than that of Ty-BatCoV HKU4, suggesting that Pi-BatCoV HKU5 may generate variants to occupy new ecological niches along with its host which faces diverse habitats. Molecular clock analysis showed that they diverged from a common ancestor with MERS-CoV at least several centuries ago. Although MERS-CoV may have diverged from potential lineage C betacoronaviruses in European bats more recently, these bat viruses were unlikely the direct ancestor of MERS-CoV. Intensive surveillance for lineage C betaCoVs in Pipistrellus and related bats with diverse habitats, and other animals from the Middle East may fill the evolutionary gap.

PMID: 23720729 [PubMed - as supplied by publisher]