Computational and molecular characterization of multiple isoforms of lfe-2 gene in nematode C. elegans

Inositol trisphosphate 3-kinases: focus on immune and neuronal signaling

The localized control of second messenger levels sculpts dynamic and persistent changes in cell physiology and structure. Inositol trisphosphate [Ins(1,4,5)P(3)] 3-kinases (ITPKs) phosphorylate the intracellular second messenger Ins(1,4,5)P(3). These enzymes terminate the signal to release Ca(2+) from the endoplasmic reticulum and produce the messenger inositol tetrakisphosphate [Ins(1,3,4,5)P(4)]. Independent of their enzymatic activity, ITPKs regulate the microstructure of the actin cytoskeleton. The immune phenotypes of ITPK knockout mice raise new questions about how ITPKs control inositol phosphate lifetimes within spatial and temporal domains during lymphocyte maturation. The intense concentration of ITPK on actin inside the dendritic spines of pyramidal neurons suggests a role in signal integration and structural plasticity in the dendrite, and mice lacking neuronal ITPK exhibit memory deficits. Thus, the molecular and anatomical features of ITPKs allow them to regulate the spatiotemporal properties of intracellular signals, leading to the formation of persistent molecular memories.

Alternatively spliced isoforms encoded by cadherin genes from C. elegansgenome

Cadherins are calcium-dependent, homophilic, cell-cell adhesion receptors that regulate morphogenesis, pattern formation and cell migration. The C. elegans Genome Sequencing Consortium has reported 12 genes from C. elegansgenome encoding members of the cadherin superfamily. Alternative splicing of eukaryotic pre-mRNAs is a mechanism for generating potentially many transcript isoforms from a single gene. Here, using a combination of various gene or exon finding programmes and several other bioinformatics tools followed by experimental validation using RT-PCR, we have studied alternative splicing pattern in the cadherin encoding genes from C. elegansgenome. We have predicted that 7 of the 12 genes encoding the cadherin superfamily undergo extensive alternative splicing and encode for 12 new unreported alternatively spliced transcripts. Most of the alternatively spliced exons were found to be present at the 5' end of genes. These new previously un-detected spliced variants in C. eleganscadherin superfamily of genes could play vital roles in explaining the way cadherins act to control the processes like cell adhesion and morphogenesis.

Identification and comparative analysis of novel alternatively spliced transcripts of RhoGEF domain encoding gene in C. elegans and C. briggsae

Y95B8A.12 gene of C. elegans encodes RhoGEF domain, which is a novel module in the Guanine nucleotide exchange factors (GEFs). Alternative splicing increases transcriptome and proteome diversification. Y95B8A.12 gene has two reported alternatively spliced transcripts by the C. elegans genome sequencing consortium. In the work presented here, we report the presence of four new spliced transcripts of Y95B8A.12 arising as a result of alternative splicing in the pre-mRNA encoded by Y95B8A.12 gene. Our methodology involved the use of various gene or exon finding programmes and several other bioinformatics tools followed by experimental validation. We have also studied alternative splicing pattern in RhoGEF domain encoding orthologues gene from C. briggsae and have obtained very similar results. These new unreported spliced transcripts, which were not detected through conventional approaches, not only point towards the extent of alternative splicing in C. elegans genes but also emphasize towards the need of analyzing genome data using a combinations of bioinformatics tools to delineate all possible gene products.