Biocomputational characterization and evolutionary analysis of bubaline dicer1 enzyme

Biocomputational analysis of evolutionary relationship between toll-like receptor and nucleotide-binding oligomerization domain-like receptors genes

Aim:

The active domains (TIR and NACHT) of the pattern recognition receptors (PRRs: Toll-like receptors [TLRs] and nucleotide-binding oligomerization domain [NOD]-like receptors [NLR], respectively) are the major hotspots of evolution as natural selection has crafted their final structure by substitution of residues over time. This paper addresses the evolutionary perspectives of the TLR and NLR genes with respect to the active domains in terms of their chronological fruition, functional diversification, and species-specific stipulation.

Materials and Methods:

A total of 48 full-length cds (and corresponding peptide) of the domains were selected as representatives of each type of PRRs, belonging to divergent animal species, for the biocomputational analyses. The secondary and tertiary structure of the taurine TIR and NACHT domains was predicted to compare the relatedness among the domains under study.

Results:

Multiple sequence alignment and phylogenetic tree results indicated that these host-specific PRRs formed entirely different clusters, with active domains of NLRs (NACHT) evolved earlier as compared to the active domains of TLRs (TIR). Each type of TLR or NLR shows comparatively less variation among the animal species due to the specificity of action against the type of microbes.

Conclusion:

It can be concluded from the study that there has been no positive selection acting on the domains associated with disease resistance which is a fitness trait indicating the extent of purifying pressure on the domains. Gene duplication could be a possible reason of genesis of similar kinds of TLRs (virus or bacteria specific).

In Silico Characterization of Functional Divergence of Two Cathelicidin Variants in Indian Sheep

The present work focuses on the in silico characterization of functional divergence of two ovine cathelicidin coding sequence (cds) variants (ie, Cath1 and Cath2) of Indian sheep. Overlapping partial cds of both the cathelicidin variants were cloned in pJet1.2/blunt vector and sequenced. Evolutionary analysis of the Cath2 and Cath1 indicated that the mammalian cathelicidins clustered separately from avian fowlicidins. The avian fowlicidins, which are very different from mammalian cathelicidins (Caths), clearly displayed signatures of purifying selection. The pairwise sequence alignments of translated amino acid sequences of these two sheep cathelicidins showed gaps in the antimicrobial domain of Cath1 variant; however, the amino terminal cathelin regions of both the Caths were conserved. Amino acid sequence analysis of full-length cathelicidins available at public database revealed that Cath1, Cath2, and Cath7 of different ruminant species (including our Cath1 and Cath2 variants) formed individual clads, suggesting that these types have evolved to target specific types of microbes. In silico analysis of Cath1 and Cath2 peptide sequences indicated that the C-terminal antimicrobial peptide domain of Cath2 is more immunogenic than that of the ovine Cath1 due to its higher positive antigenic index, making Cath1 a promising antigen for production of monoclonal antibodies.

An approach to identify the novel miRNA encoded from H. Annuus EST sequences

MicroRNAs are a newly discovered class of non-protein small RNAs with 22-24 nucleotides. They play multiple roles in biological processes including development, cell proliferation, apoptosis, stress responses and many other cell functions. In this research, several approaches were combined to make a computational prediction of potential miRNAs and their targets in Helianthus annuus (H. annuus). The already available information of the plant miRNAs present in miRBase v21 was used against expressed sequence tags (ESTs). A total of three miRNAs were detected from which one potential novel miRNA was identified following a range of strict filtering criteria. The target prediction was carried out for these three miRNAs having various targets. These targets were functionally annotated and GO terms were assigned. To study the conserved nature of the miRNAs, predicted phylogenetic analysis was carried out. These findings will significantly provide the broader picture for understanding the functions in H. annuus.