Laboratory of Molecular Biology

About: Laboratory of Molecular Biology is a facility organization based out in Cambridge, Cambridgeshire, United Kingdom. It is known for research contribution in the topics: Gene & RNA. The organization has 19395 authors who have published 24236 publications receiving 2101480 citations.

Image reconstructions of helical assemblies of the HIV-1 CA protein

Abstract: The type 1 human immunodeficiency virus (HIV-1) contains a conical capsid comprising approximately 1,500 CA protein subunits, which organizes the viral RNA genome for uncoating and replication in a new host cell. In vitro, CA spontaneously assembles into helical tubes and cones that resemble authentic viral capsids. Here we describe electron cryo-microscopy and image reconstructions of CA tubes from six different helical families. In spite of their polymorphism, all tubes are composed of hexameric rings of CA arranged with approximate local p6 lattice symmetry. Crystal structures of the two CA domains were 'docked' into the reconstructed density, which showed that the amino-terminal domains form the hexameric rings and the carboxy-terminal dimerization domains connect each ring to six neighbours. We propose a molecular model for the HIV-1 capsid that follows the principles of a fullerene cone, in which the body of the cone is composed of curved hexagonal arrays of CA rings and the ends are closed by inclusion of 12 pentagonal 'defects'.

Dopaminergic neurons in the nematode Caenorhabditis elegans

Abstract: Dopamine is the putative transmitter of eight neurons in the hermaphrodite form of the nematode Caenorhabditis elegans. These include the cephalic and deirid neurons, which are believed to be mechanosensory. The male has an additional six dopaminergic neurons in the tail. Mutants have been selected which have defects in the formaldehyde induced fluorescence and lack dopamine to varying degrees, but they are not insensitive to touch. The dopaminergic neurons of C. elegans are compared with the homologous neurons in Ascaris lumbricoides.

D1 and D2 dopamine receptor mRNA in rat brain

Abstract: Physiological and pharmacological criteria have divided dopamine receptors into D1 and D2 subtypes, and genes encoding these subtypes have recently been cloned Based on the sequences of the cloned receptors, we prepared oligodeoxynucleotide probes to map the cellular expression of the corresponding mRNAs in rat brain by in situ hybridization histochemistry These mRNAs showed largely overlapping yet distinct patterns of expression The highest levels of expression for both mRNAs were observed in the caudate-putamen, nucleus accumbens, and olfactory tubercle Within the caudate-putamen, 47 +/- 6% and 46 +/- 5% of the medium-sized neurons (10-15 microns) expressed the D1 and D2 mRNAs, respectively, and only the D2 mRNA was observed in the larger neurons (greater than 20 microns) The D1 and D2 mRNAs were expressed in most cortical regions, with the highest levels in the prefrontal and entorhinal cortices Within neocortex, D1 mRNA was observed primarily in layer 6 and D2 mRNA in layers 4-5 Within the amygdala, D1 mRNA was observed in the intercalated nuclei, and D2 mRNA in the central nucleus Within the hypothalamus, D1 mRNA was observed in the suprachiasmatic nucleus and D2 mRNA in many of the dopaminergic cell groups Within the septum, globus pallidus, superior and inferior colliculi, mammillary bodies, and substantia nigra only D2 mRNA was detected These data provide insight into the neuroanatomical basis of the differential effects of drugs that act on D1 or D2 receptors

Crystal structure of transforming growth factor-beta 2: an unusual fold for the superfamily

Abstract: The transforming growth factors-beta (TGF-beta 1 through -beta 5) are a family of homodimeric cytokines that regulate proliferation and function in many cell types. Family members have 66 to 80% sequence identity and nine strictly conserved cysteines. A crystal structure of a member of this family, TGF-beta 2, has been determined at 2.1 angstrom (A) resolution and refined to an R factor of 0.172. The monomer lacks a well-defined hydrophobic core and displays an unusual elongated nonglobular fold with dimensions of approximately 60 A by 20 A by 15 A. Eight cysteines form four intrachain disulfide bonds, which are clustered in a core region forming a network complementary to the network of hydrogen bonds. The dimer is stabilized by the ninth cysteine, which forms an interchain disulfide bond, and by two identical hydrophobic interfaces. Sequence profile analysis of other members of the TGF-beta superfamily, including the activins, inhibins, and several developmental factors, imply that they also adopt the TGF-beta fold.