Molecular Characterizations of a Novel Putative DNA- Binding Protein LvDBP23 in Marine Shrimp L. vannamei Tissues and Molting Stages Yanisa Laoong-u-thai1,2, Baoping Zhao1, Amornrat Phongdara3*, Jinzeng Yang1,4* 1 Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America, 2 Department of Chemical Engineering, Faculty of Engineering, Burapha University, Chonburi, Thailand, 3 Center for Genomics and Bioinformatics Research, Prince of Songkla University, Songkhla, Thailand, 4 College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, People’s Republic of China Abstract Background: Litopenaeus Vannamei, well known as pacific white shrimp, is the most popular shrimp in the world shrimp market. Identification and characterization of shrimp muscle regulatory genes are not only important for shrimp genetic improvement, but also facilitate comparative genomic tools for understanding of muscle development and regeneration. Methodology/Principal Findings: A novel mRNA encoding for a putative DNA-binding protein LvDBP23 was identified from Litopenaeus vannamei abdominal muscle cDNA library. The LvDBP23 cDNA contains 639 nucleotides of protein-coding sequence with deduced 212 amino acids of predicted molecular mass 23.32 kDa with glycine-rich domain at amino acid position 94–130. The mRNA sequence is successfully used for producing LvDBP23 recombinant protein in sf9 insect cell expression system. The expression of LvDBP23 mRNA is presented in abdominal muscle and swimming leg muscle, as well as other tissues including intestine, lymphoid and gill. The mRNA expression has the highest level in abdominal muscle in all tested tissues. LVDBP23 transcript during the molt cycle is highly expressed in the intermolt stage. In vitro nucleic acid- binding assays reveal that LvDBP23 protein can bind to both ssDNA and dsDNA, indicating its possible role of regulation of gene transcription. Conclusions/Significance: We are the first to report a DNA-binding protein identified from the abdominal muscle tissue of marine shrimp L. Vannamei. Its high-level specific expression during the intermot stage suggests its role in the regulation of muscle buildup during the growth phase of shrimp molt cycle. Citation: Laoong-u-thai Y, Zhao B, Phongdara A, Yang J (2011) Molecular Characterizations of a Novel Putative DNA-Binding Protein LvDBP23 in Marine Shrimp L. vannamei Tissues and Molting Stages. PLoS ONE 6(5): e19959. doi:10.1371/journal.pone.0019959 Editor: Vladimir N. Uversky, University of South Florida, United States of America Received January 25, 2011; Accepted April 7, 2011; Published May 20, 2011 Copyright: 2011 Laoong-u-thai et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The USDA-CSREES-TSTAR programs (Award # 2008-34135-19343), National Research Council of Thailand, The National Research University Project of Thailand and Office of the Higher Education Commission (Grant # SCI540527M). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: Jinzeng@hawaii.edu (JY); pamornra@yahoo.com (AP) Introduction Litopenaeus Vannamei, well known as pacific white shrimp, is the most popular shrimp in the world shrimp market [1]. Although the breeding programs for development of high-quality bloodstock have been widely carried out in several countries many shrimp researchers point out that the lack of genetic tools and understanding of molecular mechanisms of growth is still a hurdle for effective improvement of growth traits. A better understanding of muscle growth can have significant impacts on overall shrimp growth performances. Skeletal muscle is a remarkably plastic tissue. It can undergo dramatic changes in size and contractile properties during development, as well as when responding to a variety of physiological conditions. Differentiation of skeletal muscles begins when the mesodermal cells in the early embryo become attached to the myogenic lineage, which is then followed by the differentiation of fibers to specific types [2]. In mammals, this involves the expressions of skeletal muscle-specific transcrip- tion factors such as MyoD, MFY5, Myogenin, MRF4 and MEF2, which regulate the expressions of muscle-specific genes by interactions with the regulatory DNA sequences of targeted genes [2,3]. After birth, a diverse number of factors such as hormones, active and passive stretch, use and disuse, and diseases can alter the size and fiber type composition of vertebrate skeletal muscles. Crustacean muscle is structurally analogous to vertebrate skeletal muscles, with proteins organized in sarcomeres aligned along large penniform fibers. The main distinction of crustacean muscle is the different sarcomere length according to fiber type, with fast fibers organized in short sarcomeres and low mitochon- drial density, and slow tonic fibers organized in long sarcomeres with high mitochondrial density. In crustaceans, muscle also exhibits a dynamic state of continuous atrophy and restoration to facilitate withdrawal from carapace at molting. The rate of L. vannamei growth rate varies with size, sex and time of year in the coastal waters. Molting frequency varies across different species, but is normally faster in early stages, slows down with age, and is strongly influenced by ecdsyteroid hormones [4]. Muscle loss during molting does not seem to occur in abdominal muscle [5]. PLoS ONE | www.plosone.org 1 May 2011 | Volume 6 | Issue 5 | e19959