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Molecular Cloning and Analysis of Function of Nucleoside Diphosphate Kinase (NDPK) from the Scallop Chlamys farreri

Xiu-Zhen Shi, Xiao-Fan Zhao, and Jin-Xing Wang*

School of Life Sciences, Shandong University, 27 Shanda South Road, Jinan, Shandong 250100, China; fax: 86-531-88364620; E-mail: jxwang@sdu.edu.cn; shixiuzhen82@163.com; xfzhao@sdu.edu.cn

* To whom correspondence should be addressed.

Received August 29, 2007; Revision received November 22, 2007
Nucleoside diphosphate kinase (NDPK) is a key metabolic enzyme that catalyzes the synthesis of non-adenine nucleoside triphosphate (NTP) by transferring the terminal phosphate between nucleoside diphosphate (NDP) and NTP. NDPK regulates a variety of eukaryotic cellular activities including cell proliferation, development, and differentiation. The ndpk cDNA was cloned from the hemocytes of the scallop Chlamys farreri and designated Cf-ndpk. The full-length sequence of Cf-ndpk consists of 715 bp encoding a polypeptide of 153 amino acids with a calculated molecular mass of 16927.52 daltons and pI of 7.64. The mRNA expression and distribution of Cf-ndpk in both bacterially challenged and unchallenged scallops were studied by Northern blotting and in situ hybridization. The results showed that Cf-ndpk transcripts were present in hemocytes, gill, adductor muscle, mantle, digestive gland, foot, and gonad, and the expression level increased in hemocytes after bacterial challenge. Recombinant Cf-NDPK expressed in Escherichia coli could transfer the terminal phosphate between UDP and ATP. The Cf-NDPK protein was present in all tested tissues including foot, adductor muscle, digestive gland, gonad, mantle, gill, and hemolymph. It was up-regulated in hemolymph after bacterial challenge. Taken together, these results suggest that NDPK may play roles in the innate immune response of scallop.
KEY WORDS: scallop, Chlamys farreri, nucleoside diphosphate kinase (NDPK), expression profile, recombinant expression

DOI: 10.1134/S0006297908060096