Polo-Like Kinase 1 and DNA Damage Response.

Polo-like kinase 1 (Plk1), an evolutionarily conserved serine/threonine protein kinase, is a key regulator involved in the mitotic process of the cell cycle. Mounting evidence suggests that Plk1 is also involved in a variety of nonmitotic events, including the DNA damage response, DNA replication, cytokinesis, embryonic development, apoptosis, and immune regulation. The DNA damage response (DDR) includes activation of the DNA checkpoint, DNA damage recovery, DNA repair, and apoptosis. Plk1 is not only an important target of the G2/M DNA damage checkpoint but also negatively regulates the G2/M checkpoint commander Ataxia telangiectasia-mutated (ATM), promotes G2/M phase checkpoint recovery, and regulates homologous recombination repair by interacting with Rad51 and BRCA1, the key factors of homologous recombination repair. This article briefly reviews the function of Plk1 in response to DNA damage.

[A new type of spotted fever group Rickttsiaes detected in the area of Changbai mountain, Jilin province].

OBJECTIVE: In order to find out the current situation of tick-borne spotted fever in the area of Changbai mountain, Jilin province. METHODS: In this study, a polymerase chain reaction (PCR) method was developed with primers R. rOmpA 190.70p and R. rOmpA 190.701n designed on the basis of rOmpA gene, which is specific for examining spotted fever group Rickttsiaes (SFGR). Six hundred nighty-three ticks were tested and a positive PCR product amplified from D. silvarum specimen (named JL-02) was cloned and sequenced. RESULTS: The SFGR DNA was detected from D. silvarum, Haemaphysalis concinna with the positive rates were 53.81% and 7.41% respectively. Its nucleotide sequence of 587 bp rOmpA and derived amino-acids showed 100.00% similarity with nucleotide sequence of DnS 14 and 99.00% with DnS 28 from the Former Soviet Union according to the result of BLUST and CLUSTAL, which was differential from the DNA sequences of strains previously detected in China. CONCLUSION: The natural focus of tick-borne spotted fever did exist in the area of Changbai mountain. The DNA sequence of SFGR was similar to that of DnS 14, which was first reported in China.