Mitradas Panicker

Tata Institute of Fundamental Research | TIFR · Division of Neurobiology

We describe the use of a characteristic blue fluorescence to identify and isolate pluripotent human embryonic stem cells and human-induced pluripotent stem cells. The blue fluorescence emission (450-500 nm) is readily observed by fluorescence microscopy and correlates with the expression of pluripotency markers (OCT4, SOX2, and NANOG). It allows ea...

The aggregation of poly-glutamine rich proteins is closely linked with numerous neuro-degenerative disorders. In pathological and cellular models, the appearance of protein rich inclusions in cells acts as a read out of protein aggregation. The precise organization of aggregated protein in these inclusions, and their mode of growth are still poorly...

Multipotent cells from the juvenile subventricular zone (SVZ) possess the ability to differentiate into new neural cells. Depending on local signals, SVZ can generate new neurons, astrocytes, or oligodendrocytes. We previously demonstrated that activation of NMDA receptors in SVZ progenitors increases the rate of oligodendrocyte differentiation. He...

G protein-coupled receptor (GPCR) signalling is modulated by endocytosis and endosomal sorting of receptors between degradation and recycling. Differential regulation of these processes by endogenous ligands and synthetic drugs is a poorly understood area of GPCR signalling. Here, we describe remarkable diversity in the regulation of trafficking of...

We have demonstrated in our previous studies that ventral subicular lesion induces neurodegeneration of the hippocampus and produces cognitive impairment in rats. In the present study, the efficacy of transplanted green fluorescent protein (GFP)-labeled hippocampal cell line (H3-GFP) cells in establishing functional recovery in ventral subicular le...

J. Neurochem. (2010) 112, 723–732. Internalization and recycling of G-protein coupled receptors are important cellular processes regulating receptor function. These are receptor-subtype and cell type-specific. Although important, trafficking variations between receptor isoforms of different species has received limited attention. We report here, di...

The serotonergic system has been implicated in emotional and cognitive function. In particular, 5-HT(2A) (5-hydroxytrytamine receptor 2A) is attributed to a number of disorders like schizophrenia, depression, eating disorders and anxiety. 5-HT(2A), being a GPCR (G-protein coupled receptor), is important in the pharmaceutical industry as a proven ta...

'AT(4) receptors' through which Angiotensin IV (Ang IV) improves memory acquisition, were recently identified as insulin regulated aminopeptidase (IRAP). Radioligand binding studies have hitherto been performed with iodinated Ang IV in the presence of divalent cation chelators EDTA and 1,10-phenanthrolin. Hence, they referred to the apo-form of IRA...

Serotonin is reported to be present in early embryos of many species and plays an important role in early patterning. Since it is a fluorophore, it can be directly visualized using fluorescence microscopy. Here, we use three-photon microscopy to image serotonin in live pre-implantation mouse embryos. We find that it is present as puncta averaging 1...

The derivation of embryonic stem cells from mice and the development of techniques that allow for targeted manipulation of its genome have allowed for the generation of mice with desired mutations. This is what led to the announcement in Stockholm in 2007 — “The Nobel Assembly at Karolinska Institute today decided to award the Nobel Prize in Physio...

G-protein-coupled receptors or GPCRs have been a major area of study in the past decades. This is not surprising as this group, comprising a thousand-odd proteins, constitutes the largest group of signal transducers across the cell membrane and is also implicated in a vast number of diseases [1]. All major neuromodulators and some fast neurotransmi...

Serotonergic and dopaminergic systems, and their functional interactions, have been implicated in the pathophysiology of various CNS disorders. Here, we use recombinant serotonin (5-HT) 2A (5-HT2A) receptors to further investigate direct interactions between dopamine and 5-HT receptors. Previous studies in Xenopus oocytes showed that dopamine, alth...

© 2005 Optical Society of America

We report an optical tweezers based approach for efficient and controlled manipulation of neuronal growth cones. The approach exploits asymmetric transverse gradient force created in a line optical tweezers to transport actin monomers in the desired growth direction. With this approach induction of artificial growth cones from the neuronal cell bod...

Hot water epilepsy (HWE) is a benign and rare form of reflex epilepsy that occurs most commonly in humans. Bdm1 is one of the proteins whose mRNA transcript is overexpressed during HWE in a rat model. We show, by sequence analysis and fold recognition methods, that Bdm1 has strong structural similarities to alpha/beta hydrolases like the thioestera...

Serotonin (5-HT), a major neurotransmitter, has a large number of G protein-coupled receptors in mammals. On activation by exposure to their ligand, 5-HT(2) receptor subtypes increase IP(3) levels and undergo desensitization and internalization. To visualize the receptor in cells during these processes, we have constructed a 5-HT(2A)-enhanced GFP (...

The rho 1 gamma -aminobutyrate receptor (GABArho 1) is expressed predominantly in the retina and forms homomeric GABA-gated Cl- channels that are clearly different from the multisubunit GABAA receptors. In contrast to these, GABArho 1 receptors desensitize very little and are not blocked by bicuculline. In addition to GABArho 1, two new variants we...

To investigate the receptor-channel coupling pathway, the coding region of the 5-HT1a receptor was subcloned into two plasmid vectors pSP64(polyA+) and pSP64T. Compared to the original 5-HT1a receptor construct G-21, both new constructs increased greatly the expression of functional 5-HT1a receptors in Xenopus oocytes, which developed large inward...

The mouse serotonin 1F (5-HT1F) receptor is encoded by at least three transcripts in mouse brain. These transcripts are expressed predominantly in cortex and hippocampus. Similar transcripts are seen in Northern analysis of rat brain mRNA. 5' RACE showed a predominant transcription start site around 350 bp upstream of the translational start presen...

THE mouse serotonin 1F (5-HT1F) receptor is encoded by at least three transcripts in mouse brain. These transcripts are expressed predominantly in cortex and hippocampus. Similar transcripts are seen in Northern analysis of rat brain mRNA. 5' RACE showed a predominant transcription start site around 350 bp upstream of the translational start presen...

Using a traD overexpression plasmid, we purified the F sex factor TraD protein in milligram quantities. The purified protein has an apparent molecular weight of 82,000 and an amino acid composition rich in acidic residues. Using specific antibodies, TraD was localized to the inner membrane of F+ cells under conditions where it is produced in physio...

Using electrophysiological techniques, we studied interactions of dopamine and selected dopaminergic drugs with serotonin (5-hydroxytryptamine; 5-HT) receptors expressed in Xenopus oocytes by RNAs transcribed from cloned cDNAs. Oocytes showing strong expression of 5-HT1c and 5-HT2 receptors became weakly responsive to the neurotransmitter dopamine,...

The gene product of F tral is a bifunctional protein which nicks and unwinds the F plasmid during conjugal DNA transfer. Further biochemical characterization of the Tral protein reveals that it has a second, much lower, Km for ATP hydrolysis, in addition to that previously identified. Measurement of the single-stranded DNA-stimulated ATPase rate in...

The modulation of K+ channels by serotonin (5-HT) receptors was studied by coinjecting Xenopus oocytes with mRNA transcribed in vitro from a cloned 5-HT 1C subtype (5-HT1C) receptor gene, together with size-fractionated mRNA isolated from rat cerebral cortex that expresses K+ channels. After intracellular loading with EGTA to block Ca2(+)-dependent...

Membrane currents evoked by serotonin (5-HT) were studied in Xenopus oocytes injected with rat brain mRNA. Intracellular EGTA was used to abolish the Ca2(+)-dependent oscillatory Cl- current to 5-HT, revealing an underlying smooth inward current. This was associated with a decreased membrane conductance, was antagonized by Ba2+ and Zn2+ (but not TE...

A fusion protein containing a Drosophila choline acetyltransferase (ChAT) cDNA insert was purified from a lambda gtll lysate of Escherichia coli. The cDNA insert, which contained a 728-amino acid coding region for ChAT, was used for immunizing rabbits. Three different antisera were produced that could recognize native Drosophila ChAT with low titer...

Donor bacteria containing JCFL39, a temperature-sensitive traD mutant of the F sex factor, were used at the nonpermissive temperature to accumulate stable mating pairs with recipient cells. At this stage in conjugation, extracellular F pili were removed by treatment with 0.01% sodium dodecyl sulfate. Upon then shifting to the permissive temperature...

Previous attempts to clone the Escherichia coli polA+ gene onto a high copy number plasmid were unsuccessful. The apparent lethality of unregulated overproduction of DNA polymerase I can be eliminated by cutting at a BglII site 100 nucleotides upstream from the ATG start codon of the polA gene. This permitted the construction of plasmid pMP5 which...