scholarly journals Signal Sequence Conservation and Mature Peptide Divergence Within Subgroups of the Murine beta-Defensin Gene Family

2003 ◽  
Vol 20 (3) ◽  
pp. 460-470 ◽  
Author(s):  
G. M. Morrison
Keyword(s):  
Gene Family ◽  
Signal Sequence ◽  
Sequence Conservation ◽  
Mature Peptide ◽  
Defensin Gene

scholarly journals daf-7-related TGF-β homologues from Trichostrongyloid nematodes show contrasting life-cycle expression patterns

Parasitology ◽  
2009 ◽  
Vol 137 (1) ◽  
pp. 159-171 ◽  
Author(s):  
H. J. McSORLEY ◽  
J. R. GRAINGER ◽  
Y. HARCUS ◽  
J. MURRAY ◽  
A. J. NISBET ◽  
...  
Keyword(s):  
Amino Acids ◽  
Life Cycle ◽  
Gene Family ◽  
Transforming Growth Factor ◽  
Signal Sequence ◽  
Expression Patterns ◽  
Transforming Growth Factor Β ◽  
Laboratory Model ◽  
Parasitic Nematodes ◽  
Nippostrongylus Brasiliensis

SUMMARYThe transforming growth factor-β (TGF-β) gene family regulates critical processes in animal development, and plays a crucial role in regulating the mammalian immune response. We aimed to identify TGF-β homologues from 2 laboratory model nematodes (Heligmosomoides polygyrus and Nippostrongylus brasiliensis) and 2 major parasites of ruminant livestock (Haemonchus contortus and Teladorsagia circumcincta). Parasite cDNA was used as a template for gene-specific PCR and RACE. Homologues of the TGH-2 subfamily were isolated, and found to differ in length (301, 152, 349 and 305 amino acids respectively), with variably truncated N-terminal pre-proteins. All contained conserved C-terminal active domains (>85% identical over 115 amino acids) containing 9 cysteine residues, as in C. elegans DAF-7, Brugia malayi TGH-2 and mammalian TGF-β. Surprisingly, only the H. contortus homologue retained a conventional signal sequence, absent from shorter proteins of other species. RT-PCR assays of transcription showed that in H. contortus and N. brasiliensis expression was maximal in the infective larval stage, and very low in adult worms. In contrast, in H. polygyrus and T. circumcincta, tgh-2 transcription is higher in adults than infective larvae. The molecular evolution of this gene family in parasitic nematodes has diversified the pre-protein and life-cycle expression patterns of TGF-β homologues while conserving the structure of the active domain.

scholarly journals Molecular Cloning of the Gene for a Conserved Major Immunoreactive 28-Kilodalton Protein of Ehrlichia canis: a Potential Serodiagnostic Antigen

1999 ◽  
Vol 6 (3) ◽  
pp. 392-399 ◽  
Author(s):  
Jere W. McBride ◽  
Xue-jie Yu ◽  
David H. Walker
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Gene Family ◽  
Signal Sequence ◽  
Ehrlichia Canis ◽  
Variable Regions ◽  
Reading Frame ◽  
Cowdria Ruminantium ◽  
Canine Ehrlichiosis ◽  
Gene Copies

ABSTRACT A gene encoding a 28-kDa protein of Ehrlichia canis was cloned, sequenced, and expressed, and a comparative molecular analysis with homologous genes of E. canis, Cowdria ruminantium, and Ehrlichia chaffeensis was performed. The complete gene has an 834-bp open reading frame encoding a protein of 278 amino acids with a predicted molecular mass of 30.5 kDa. An N-terminal signal sequence was identified, suggesting that the protein undergoes posttranslational modification to a mature 27.7-kDa protein (P28). The E. canis p28 gene has significant nucleic acid and amino acid sequence homologies with the E. chaffeensisouter membrane protein-1 (omp-1) gene family, with theCowdria ruminantium map-1 gene, and with other E. canis 28-kDa-protein genes. Southern blotting revealed the presence of at least two additional homologous p28 gene copies in the E. canis genome, confirming thatp28 is a member of a polymorphic multiple-gene family. Amino acid sequence analysis revealed that E. canis P28 has four variable regions, and it shares similar surface-exposed regions, antigenicity, and T-cell motifs with E. chaffeensis P28. The p28 genes from seven different E. canisisolates were identical, indicating that the gene for this major immunoreactive protein is highly conserved. In addition, reactivity of sera from clinical cases of canine ehrlichiosis with the recombinant P28 demonstrated that the recombinant protein may be a reliable serodiagnostic antigen.

scholarly journals Origin of a novel protein-coding gene family with similar signal sequence in Schistosoma japonicum

BMC Genomics ◽  
2012 ◽  
Vol 13 (1) ◽  
pp. 260 ◽  
Author(s):  
Evaristus Mbanefo ◽  
Yu Chuanxin ◽  
Mihoko Kikuchi ◽  
Mohammed Shuaibu ◽  
Daniel Boamah ◽  
...  
Keyword(s):  
Gene Family ◽  
Schistosoma Japonicum ◽  
Signal Sequence ◽  
Protein Coding ◽  
Novel Protein

scholarly journals Molecular characterization of a novel β-defensin isoform from the red-toothed trigger fish, Odonus niger (Ruppel, 1836)

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
S. Neelima ◽  
K. Archana ◽  
P. P. Athira ◽  
M. V. Anju ◽  
V. V. Anooja ◽  
...  
Keyword(s):  
Immune System ◽  
Amino Acid ◽  
Antimicrobial Peptides ◽  
Innate Immune System ◽  
Disulfide Bonds ◽  
Signal Sequence ◽  
Phylogenetic Analyses ◽  
Functional Characterization ◽  
Innate Immune ◽  
Mature Peptide

Abstract Background The concern regarding a post-antibiotic era with increasing drug resistance by pathogens imposes the need to discover alternatives for existing antibiotics. Antimicrobial peptides (AMPs) with their versatile therapeutic properties are a group of promising molecules with curative potentials. These evolutionarily conserved molecules play important roles in the innate immune system of several organisms. The β-defensins are a group of cysteine rich cationic antimicrobial peptides that play an important role in the innate immune system by their antimicrobial activity against the invading pathogens. The present study deals with a novel β-defensin isoform from the red-toothed trigger fish, Odonus niger. Total RNA was isolated from the gills, cDNA was synthesized and the β-defensin isoform obtained by polymerase chain reaction was cloned and subjected to structural and functional characterization in silico. Results A β-defensin isoform could be detected from the gill mRNA of red-toothed trigger fish, Odonus niger. The cDNA encoded a 63 amino acid peptide, β-defensin, with a 20 amino acid signal sequence followed by 43 amino acid cationic mature peptide (On-Def) having a molecular weight of 5.214 kDa and theoretical pI of 8.89. On-Def possessed six highly conserved cysteine residues forming disulfide bonds between C1–C5, C2–C4, and C3–C6, typical of β-defensins. An anionic pro-region was observed prior to the β-defensin domain within the mature peptide. Clustal alignment and phylogenetic analyses revealed On-Def as a group 2 β-defensin. Furthermore, it shared some structural similarities and functional motifs with β-defensins from other organisms. On-Def was predicted to be non-hemolytic with anti-bacterial, anti-viral, anti-fungal, anti-cancer, and immunomodulatory potential. Conclusion On-Def is the first report of a β-defensin from the red-toothed trigger fish, Odonus niger. The antimicrobial profile showed the potential for further studies as a suitable candidate for antimicrobial peptide therapeutics.

scholarly journals Yeast KRE2 defines a new gene family encoding probable secretory proteins, and is required for the correct N-glycosylation of proteins.

Genetics ◽  
1992 ◽  
Vol 130 (2) ◽  
pp. 273-283 ◽  
Author(s):  
K Hill ◽  
C Boone ◽  
M Goebl ◽  
R Puccia ◽  
A M Sdicu ◽  
...  
Keyword(s):  
Gene Family ◽  
Secretory Pathway ◽  
Signal Sequence ◽  
Secretory Proteins ◽  
Chromosome 15 ◽  
Amino Acid Residues ◽  
New Gene ◽  
New Yeast ◽  
Average Size

Abstract We have cloned, sequenced and disrupted the KRE2 gene of Saccharomyces cerevisiae, identified by killer-resistant mutants with a defective cell wall receptor for the toxin. The KRE2 gene is close to PHO8 on chromosome 4, and encodes a predicted 49-kD protein, Kre2p, that probably enters the secretory pathway. Haploid cells carrying a disruption of the KRE2 locus grow more slowly than wild-type cells at 30 degrees, and fail to grow at 37 degrees. At 30 degrees, kre2 mutants showed altered N-linked glycosylation of proteins, as the average size of N-linked outer chains was reduced. We identified two other genes, YUR1 on chromosome 10, and KTR1 on chromosome 15, whose predicted products share 36% identity with Kre2p over more than 300 amino acid residues. Yur1p has an N-terminal signal sequence like Kre2p, while Ktr1p has a predicted topology consistent with a type 2 membrane protein. In all cases the conserved regions of these proteins appear to be on the lumenal side of secretory compartments, suggesting related function. KRE2, KTR1 and YUR1 define a new yeast gene family.

Rapid evolution and diversification of mammalian α-defensins as revealed by comparative analysis of rodent and primate genes

2004 ◽  
Vol 20 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Amar Patil ◽  
Austin L. Hughes ◽  
Guolong Zhang
Keyword(s):  
Gene Family ◽  
Host Defense ◽  
Phylogenetic Analyses ◽  
Mammalian Species ◽  
Rapid Evolution ◽  
Primate Species ◽  
Ecological Niches ◽  
Defensin Gene ◽  
New Genes ◽  
Species Specific

Mammalian α-defensins constitute a family of cysteine-rich, cationic antimicrobial peptides produced by phagocytes and intestinal Paneth cells, playing an important role in innate host defense. Following comprehensive computational searches, here we report the discovery of complete repertoires of the α-defensin gene family in the human, chimpanzee, rat, and mouse with new genes identified in each species. The human genome was found to encode a cluster of 10 distinct α-defensin genes and pseudogenes expanding 132 kb continuously on chromosome 8p23. Such α-defensin loci are also conserved in the syntenic chromosomal regions of chimpanzee, rat, and mouse. Phylogenetic analyses showed formation of two distinct clusters with primate α-defensins forming one cluster and rodent enteric α-defensins forming the other cluster. Species-specific clustering of genes is evident in nonprimate species but not in the primates. Phylogenetically distinct subsets of α-defensins also exist in each species, with most subsets containing multiple members. In addition, natural selection appears to have acted to diversify the functionally active mature defensin region but not signal or prosegment sequences. We concluded that mammalian α-defensin genes may have evolved from two separate ancestors originated from β-defensins. The current repertoires of the α-defensin gene family in each species are primarily a result of repeated gene duplication and positive diversifying selection after divergence of mammalian species from each other, except for the primate genes, which were evolved prior to the separation of the primate species. We argue that the presence of multiple, divergent subsets of α-defensins in each species may help animals to better cope with different microbial challenges in the ecological niches which they inhabit.

Defensin gene family in Medicago truncatula: structure, expression and induction by signal molecules

2005 ◽  
Vol 58 (3) ◽  
pp. 385-399 ◽  
Author(s):  
Jennifer N. Hanks ◽  
Anita K. Snyder ◽  
Michelle A. Graham ◽  
Rajiv K. Shah ◽  
Laura A. Blaylock ◽  
...  
Keyword(s):  
Gene Family ◽  
Medicago Truncatula ◽  
Signal Molecules ◽  
Defensin Gene

scholarly journals Transcriptomic Profiling Reveals Extraordinary Diversity of Venom Peptides in Unexplored Predatory Gastropods of the Genus Clavus

2020 ◽  
Vol 12 (5) ◽  
pp. 684-700
Author(s):  
Aiping Lu ◽  
Maren Watkins ◽  
Qing Li ◽  
Samuel D Robinson ◽  
Gisela P Concepcion ◽  
...  
Keyword(s):  
Signal Sequence ◽  
Structural Similarity ◽  
Gene Families ◽  
Venom Gland ◽  
Mature Peptide ◽  
Secretion Signal ◽  
Living Species ◽  
Evolutionary Success ◽  
Peptide Toxins ◽  
Conus Venom

Abstract Predatory gastropods of the superfamily Conoidea number over 12,000 living species. The evolutionary success of this lineage can be explained by the ability of conoideans to produce complex venoms for hunting, defense, and competitive interactions. Whereas venoms of cone snails (family Conidae) have become increasingly well studied, the venoms of most other conoidean lineages remain largely uncharacterized. In the present study, we present the venom gland transcriptomes of two species of the genus Clavus that belong to the family Drilliidae. Venom gland transcriptomes of two specimens of Clavus canalicularis and two specimens of Clavus davidgilmouri were analyzed, leading to the identification of a total of 1,176 putative venom peptide toxins (drillipeptides). Based on the combined evidence of secretion signal sequence identity, entire precursor similarity search (BLAST), and the orthology inference, putative Clavus toxins were assigned to 158 different gene families. The majority of identified transcripts comprise signal, pro-, mature peptide, and post-regions, with a typically short (<50 amino acids) and cysteine-rich mature peptide region. Thus, drillipeptides are structurally similar to conotoxins. However, convincing homology with known groups of Conus toxins was only detected for very few toxin families. Among these are Clavus counterparts of Conus venom insulins (drillinsulins), porins (drilliporins), and highly diversified lectins (drillilectins). The short size of most drillipeptides and structural similarity to conotoxins were unexpected, given that most related conoidean gastropod families (Terebridae and Turridae) possess longer mature peptide regions. Our findings indicate that, similar to conotoxins, drillipeptides may represent a valuable resource for future pharmacological exploration.

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