Temporin-1SKc

A previous study led to the isolation of antimicrobial peptides belonging to the temporin and brevinin-2 families from a pooled extract of the skin of adult specimens of the Japanese mountain brown frog Rana ornativentris Werner 1903. In order to ascertain whether individual frogs expressed the full complement of temporin genes, we individually cloned cDNAs encoding the temporin precursors from total RNA extracted from the skins of 12 frogs by RT-PCR using a set of preprotemporin-specific primers. All the specimens examined contained mRNAs directing the synthesis of the novel, but inactive, temporin-1Oe (ILPLLGNLLNGLL x NH2). Nucleotide sequence analysis revealed marked polymorphism among individual frogs. Twenty-seven distinct preprotemporin-1Oe mRNAs were identified that contained synonymous substitutions in the antimicrobial peptide region and both synonymous and non-synonymous substitutions in the signal peptide and intervening sequence regions. Up to eight preprotemporin-1Oe mRNA variants were found within a single frog. In addition, several cDNAs encoding preprotemporin-1Oa and -1Ob and a single cDNA encoding preprotemporin-1Oc were characterized. Peptidomic analysis of norepinephrine-stimulated skin secretions revealed the presence of temporin-1Oe, temporin-1Of (SLILKGLASIAKLF x NH2), temporin-1Og (FLSSLLSKVVSLFT x NH2), four members of the ranatuerin-2 family and one member of the palustrin-2 family in addition to previously characterized temporin and brevinin-2 peptides.

Amphibian skin antimicrobial peptides exhibit a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacterium and cytotoxic activity responsible for inhibiting the growth of cancer cells. In this present study, six cDNAs encoding antimicrobial peptide precursors were cloned from the skin of Chinese brown frog, Rana chensinensis by RT-PCR and 3'-RACE procedure and identified as preprotemporin-1CEa, preprotemporin-1CEb, preprotemporin-1CEc, preprobrevinin-1CEa, preprobrevinin-1CEb, and preprochensinin-1, respectively. The nucleotide sequences of cDNA encoding 59-65 amino acid composed of 289-315 bp. Preprotemporin-1CEa, preprotemporin-1CEb and preprotemporin-1CEc are members of temporin family, which usually are short, hydrophobic, and C-terminally alpha-amidated antimicrobial peptides. Preprobrevinin-1CEa and preprobrevinin-1CEb were identified as the members of the brevinin-1 family of antimicrobial peptides since both peptides contain "RANA box" that it's responsible for forming Cys-bridged cyclic heptapeptides at the C-terminal region of peptide. The nucleotide acid sequence and the deduced amino acid Sequence of preprochensinin-1 were not found to be identity with any known amphibian skin defensive peptides, so, preprochensinin-1 was identified as a novel peptide precursor. Four of bioactive peptides: temporin-1CEa, temporin-1CEb, brevinin-1CEa and chensinin-1 were synthesized to investigate their antimicrobial, anticancer and haemolysis activities. The results showed that all of the synthesized antimicrobial peptides in this study inhibited the growth of the Gram-positive bacterium, and exhibited the anticancer activity against the growth of MCF-7 cells and HeLa cells. Analysis of the R. chensinensis bioactive peptides and their gene expression will be beneficial for preservation of this species.

Previous studies led to the isolation from skin extracts of Oki Tago's brown frog, Rana tagoi okiensis of five antimicrobial peptides belonging to the brevinin-1 (brevinin-1TOa), temporin (temporin-TOa and -TOb), and ranatuerin-2 (ranatuerin-2TOa and -2TOb) families, and bradykinin (BK) identical to mammalian BK. Using the reverse-transcription polymerase chain reaction (RT-PCR), we have now cloned from skin total RNA preparations cDNAs encoding biosynthetic precursors of brevinin-1TOa and brevinin-1TOb (containing the substitution Gly(1)-->Val), temporin-TOa and -TOb, and ranatuerin-2TOa and -2TOb. In addition, three cDNA clones encoding preprobradykinins were obtained that contained either one, two, or three tandem repeats of the sequence of BK followed by the sequence of [Thr(6)]-BK. In tissue expression analyses, preprobrevinin-1, preprotemporin, and preproranatuerin-2 gene transcripts were detected at higher levels in brain compared with peripheral tissues (heart, small intestine, kidney, liver lung, skeletal muscle, stomach, and testis). RT-PCR of brain RNA resulted in the amplification of cDNAs encoding ranatuerin-2TOc and ranatuerin-2TOd that contained the amino acid substitutions Lys(6)-->Arg and Ala(14)-->Thr, respectively compared with ranatuerin-2TOb. cDNAs encoding preprobrevinin-1TOa and preprotemporin-TOa were amplified from brain RNA as well as a second preprotemporin cDNA that contained a 10-nucleotide insertion that introduced a frame shift resulting in a premature stop codon. A cDNA encoding a novel peptide, DK25 (DVNDLKNLCAKTHNLLPMCAMFGKK) was amplified from brain RNA but neither DK25 nor its putative post-translationally modified form, DF22-amide (DVNDLKNLCAKTHNLLPMCAMF.NH(2)) displayed antimicrobial or hemolytic activities.