To rapidly and accurately manipulate genome such as gene deletion, insertion and site mutation, the whole genome of a very virulent strain Md5 of Marek's disease virus (MDV) was inserted into bacterial artificial chromosome (BAC) through homogeneous recombination. The recombinant DNA was electroporated into DH10B competent cells and identified by PCR and restriction fragment length polymorphism analysis. An infectious clone of Md5BAC was obtained following transfection into chicken embryo fibroblast (CEF) cells. Furthermore, a lorf10 deletion mutant was constructed by two step Red-mediated homologous recombination. To confirm the specific role of gene deletion, the lorf10 was reinserted into the original site of MDV genome to make a revertant strain. All the constructs were rescued by transfection into CEF cells, respectively. The successful packaging of recombinant viruses was confirmed by indirect immunofluorescence assay. The results of growth kinetics assay and plaques area measurement showed that the lorf10 is dispensable for MDV propagation in vitro. Overall, this study successfully constructed an infectious BAC clone of MDV and demonstrated its application in genome manipulation; the knowledge gained from our study could be further applied to other hepesviruses.
Animals ; Chick Embryo ; Chickens ; Chromosomes, Artificial, Bacterial ; DNA, Recombinant ; Herpesvirus 2, Gallid/genetics* ; Marek Disease

Tinosporae Radix， as a traditional Chinese medicinal herb， is the dried root tuber of Tinospora sagittata or T. capillipes. It was first recorded in the Compendium of Materia Medica Supplement in the Qing Dynasty and included in the previous edition of the Chinese Pharmacopoeia. Tinosporae Radix is excavated in autumn and winter and used after removing fibrous roots， washing， and drying. It is indicated for sore throat， carbuncle boils poison， waist and abdominal pain， and various heat syndromes and is commonly used to treat chronic inflammation. Its efficacy is significantly known as “broad-spectrum antibiotics in Zhuang medicine”. Tinosporae Radix is a traditional Chinese medicinal herb often taken by Zhuang and Yao nationalities in Guangxi province and has a wide range of application and development values and research significance. Modern studies have shown that Tinosporae Radix contains diterpenoids， alkaloids， sterols， anthraquinones， glycosides， fatty acids， volatile oils， and other compounds， which have many pharmacological activities such as anti-inflammatory and analgesic， antibacterial and antibacterial， antioxidant， anti-diabetic， and anti-tumor and anti-cancer effects， and it has achieved good efficacy in inhibiting inflammation and treating sore throat and other diseases. In recent years， there have been many research reports on the status， chemical constituents， pharmacological action， clinical application， and quality evaluation of Tinosporae Radix resources， but there is no systematic review and introduction at present. By consulting the literature and combining it with modern research， this paper systematically summarizes and collates Tinosporae Radix resources to provide guidance for the comprehensive development and utilization of Tinosporae Radix resources and subsequent in-depth study.