Identification, tissue specific expression analysis and functional characterization of arrestin gene (ARRDC) in the earthworm Eudrilus eugeniae: a molecular hypothesis behind worm photoreception.

BACKGROUND: The arrestin domain containing proteins (ARRDCs) are crucial adaptor proteins assist in signal transduction and regulation of sensory physiology. The molecular localization of the ARRDC gene has been confined mainly to the mammalian system while in invertebrates the expression pattern was not addressed significantly. The present study reports the identification, tissue specific expression and functional characterization of an ARRDC transcript in earthworm, Eudrilus eugeniae. METHODS AND RESULTS: The coding region of earthworm ARRDC transcript was 1146 bp in length and encoded a protein of 381 amino acid residues. The worm ARRDC protein consists of conserved N-terminal and C-terminal regions and showed significant homology with the ARRDC3 sequence of other species. The tissue specific expression analysis through whole mount in-situ hybridization denoted the expression of ARRDC transcript in the central nervous system of the worm which includes cerebral ganglion and ventral nerve cord. Besides, the expression of ARRDC gene was observed in the epidermal region of earthworm skin. The functional characterization of ARRDC gene was assessed through siRNA silencing and the gene was found to play key role in the light sensing ability and photophobic movement of the worm. CONCLUSIONS: The neuronal and dermal expression patterns of ARRDC gene and its functional characterization hypothesized the role of the gene in assisting the photosensory cells to regulate the process of photoreception and phototransduction in the worm.

Earthworms and vermicompost: an eco-friendly approach for repaying nature's debt.

The steady increase in the world's population has intensified the need for crop productivity, but the majority of the agricultural practices are associated with adverse effects on the environment. Such undesired environmental outcomes may be mitigated by utilizing biological agents as part of farming practice. The present review article summarizes the analyses of the current status of global agriculture and soil scenarios; a description of the role of earthworms and their products as better biofertilizer; and suggestions for the rejuvenation of such technology despite significant lapses and gaps in research and extension programs. By maintaining a close collaboration with farmers, we have recognized a shift in their attitude and renewed optimism toward nature-based green technology. Based on these relations, it is inferred that the application of earthworm-mediated vermitechnology increases sustainable development by strengthening the underlying economic, social and ecological framework.

Identification of shorter length lamin A protein in mouse ear cartilage tissue.

Lamin A is an intermediate filament protein which is cleaved by the enzyme, FACE 1 at VTRSY↓L. The cleavage is the final step in the production of the mature lamin A protein. The mature lamin A protein localizes in the inner membrane of the nucleus. The mutation in the lamin A gene causes many diseases, including accelerated aging. It is known that the protein is not expressed in neuronal cells of the brain. Many splicing variants of the lamin A gene have been reported. In this study, the amino acid sequence VTRSY (a penta-peptide repeat) was found in three different sites of the C-terminal end of the lamin A protein, the protein expressed in cells of ear cartilage tissues is shorter than the protein expressed in cells of the skin tissues. Using two lamin A antibodies, it was found that the amino acid sequence between penta-peptide 2 and 3 is missing in lamin A protein that was expressed in the cells of mouse ear cartilage tissue, besides the RT-PCR data confirmed that the corresponding coding sequence between the penta repeat 2 and 3 is intact. Cleavage may occur at the penta-peptide (VTRSY) at site 3 in the lamin A tail of mouse ear cartilage.

Conserved lamin A protein expression in differentiated cells in the earthworm Eudrilus eugeniae.

Lamin A is an intermediate filament protein found in most of the differentiated vertebrate cells but absent in stem cells. It shapes the skeletal frame structure beneath the inner nuclear membrane of the cell nucleus. As there are few studies of the expression of lamin A in invertebrates, in the present work, we have analyzed the sequence, immunochemical conservation and expression pattern of lamin A protein in the earthworm Eudrilus eugeniae, a model organism for tissue regeneration. The expression of lamin A has been confirmed in E. eugeniae by immunoblot. Its localization in the nuclear membrane has been observed by immunohistochemistry using two different rabbit anti-sera raised against human lamin A peptides, which are located at the C-terminus of the lamin A protein. These two antibodies detected 70 kDa lamin A protein in mice and a single 65 kDa protein in the earthworm. The Oct-4 positive undifferentiated blastemal tissues of regenerating earthworm do not express lamin A, while the Oct-4 negative differentiated cells express lamin A. This pattern was also confirmed in the earthworm prostate gland. The present study is the first evidence for the immunochemical identification of lamin A and Oct-4 in the earthworm. Along with the partial sequence obtained from the earthworm genome, the present results suggest that lamin A protein and its expression pattern is conserved from the earthworm to humans.

Activity-dependent expression of miR-132 regulates immediate-early gene induction during olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx.

The activity-dependent expression of immediate-early genes (IEGs) and microRNA (miR)-132 has been implicated in synaptic plasticity and the formation of long-term memory (LTM). In the present study, we show that olfactory training induces the expression of IEGs (EGR-1, C-fos, C-jun) and miR-132 at similar time scale in olfactory bulb (OB) of Cynopterus sphinx. We examined the role of miR-132 in the OB using antisense oligodeoxynucleotide (AS-ODN) and demonstrated that a local infusion of AS-ODN in the OB 2h prior to training impaired olfactory memory formation in C. sphinx. However, the infusion of AS-ODN post-training did not cause a deficit in memory formation. Furthermore, the inhibition of miR-132 reduced the olfactory training-induced expression of IEGs and post synaptic density protein-95 (PSD-95) in the OB. Additionally, we show that miR-132 regulates the activation of calcium/calmodulin-dependent protein kinase-II (CaMKII) and cAMP response element binding protein (CREB), possibly through miR-148a. These data suggest that olfactory training induces the expression of miR-132 and IEGs, which in turn activates post-synaptic proteins that regulate olfactory memory formation.

Perturbation of wild-type lamin A metabolism results in a progeroid phenotype.

Mutations in the lamin A/C gene cause the rare genetic disorder Hutchinson-Gilford progeria syndrome (HGPS). The prevalent mutation results in the production of a mutant lamin A protein with an internal 50 amino acid deletion which causes a cellular aging phenotype characterized by growth defects, limited replicative lifespan, and nuclear membrane abnormalities. However, the relevance of these findings to normal human aging is unclear. In this study, we demonstrate that increased levels of wild-type lamin A in normal human cells result in decreased replicative lifespan and nuclear membrane abnormalities that lead to apoptotic cell death and senescence in a manner that is strongly reminiscent of the phenotype shown by HGPS cells. In contrast to the accelerated aging defects observed in HGPS cells, the progeroid phenotype resulting from increased expression of wild-type lamin A can be rescued by overexpression of ZMPSTE24, the metalloproteinase responsible for the removal of the farnesylated carboxyl terminal region of lamin A. Furthermore, farnesyltransferase inhibitors also serve to reverse the progeroid phenotype resulting from increased lamin A expression. Significantly, cells expressing elevated levels of lamin A display abnormal lamin A localization and similar alterations in the nuclear distribution of lamin A are also observed in cells from old-age individuals. These data demonstrate that the metabolism of wild-type lamin A is delicately poised and even in the absence of disease-linked mutations small perturbations in this system are sufficient to cause prominent nuclear defects and result in a progeroid phenotype.