title: Structural characterization and expression analysis of a beta-thymosin homologue (Tβ) in disk abalone, Haliotis discus discus.
abstract: Repertoires of proteins and small peptides play numerous physiological roles as hormones, antimicrobial peptides, and cellular signaling factors. The beta-thymosins are a group of small acidic peptides involved in processes such as actin sequestration, neuronal development, wound healing, tissue repair, and angiogenesis. Recent characterization of the beta thymosins as immunological regulators in invertebrates led to our identification and characterization of a beta-thymosin homologue (Tβ) from Haliotis discus discus. The cDNA possessed an ORF of 132 bp encoding a protein of 44 amino acids with a molecular mass of 4977 Da. The amino acid sequence shows high identity with another molluskan beta-thymosin and has a characteristic actin binding motif (LKKTET) and glutamyl donors. Phylogenetic analysis showed a close relationship with molluskan homologues, as well as its distinct identity and common ancestral origin. Genomic analysis revealed a 3 exon-2 intron structure similar to the other homologues. In silico promoter analysis also revealed significant transcription factor binding sites, providing evidence for the expression of this gene under different cellular conditions, including stress or pathogenic attack. Tissue distribution profiling revealed a ubiquitous presence in all the examined tissues, but with the highest expression in mantle and hemocyte. Immune challenge with lipopolysaccharide, poly I:C and Vibrio parahemolyticus induced beta-thymosin expression in gill and hemocytes, affirming an immune-related role in invertebrates.
authors.affiliation: Department of Marine Life Sciences, School of Marine Biomedical Sciences, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
authors.forename: Saranya Revathy
authors.initials: SR
authors.lastname: Kasthuri
authors.forename: H K A
authors.initials: HK
authors.lastname: Premachandra
authors.forename: Navaneethaiyer
authors.initials: N
authors.lastname: Umasuthan
authors.forename: Ilson
authors.initials: I
authors.lastname: Whang
authors.forename: Jehee
authors.initials: J
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049851:Gastropoda / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000276:immunology; D054884:Host-Pathogen Interactions; D008070:Lipopolysaccharides / Q000494:pharmacology; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013947:Thymosin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014736:Vibrio parahaemolyticus / Q000276:immunology
chemical_list: D008070:Lipopolysaccharides; D012333:RNA, Messenger; D013947:Thymosin
keywords: AML-1a; AP-1; BAC; Beta thymosin; Brn-2; C/EBPα; CCAAT-enhancer binding protein alpha; CFU; Egr-1; Genomic characterization; HSF; Haliotis discus discus; IL-3; IRF-2; LPS; Lyf-1; ORF; Oct-1; PAMP; PCR; Poly I:C; RAR-related orphan receptor A; ROR-α; STAT; Tβ; UTR; Vibrio parahemolyticus; activator protein-1; acute myeloid leukemia-1a; bacterial artificial chromosome; beta thymosin; brain-2; cDNA; colony forming units; complementary DNA; early growth response 1; heat shock factor; i.m.; interferon regulatory factor-2; interleukin-3; intramuscular; lipopolysaccharide; lymphoid transcription factor-1; octamer-binding transcription factor-1; open reading frame; pathogen-associated molecular pattern; poly I:C; polyinosinic:polycytidylic acid; polymerase chain reaction; qRT-PCR; quantitative real-time RT-PCR; signal transducer and activator of transcription; untranslated region