"Of particular interest" -

in the opinion of neurobiologists. Papers "of particular interest" selected, from the previous year's literature, by the authors

of reviews in the section on Neuronal and Clial Cell Biology in the October 1992 issue of Current Opinion in Neurobiology.

Cell adhesion molecules, second messengers and axonal growth se l ec t ed by Patrick D o h e r t y and Frank S. Walsh GRUMET M, MAURO V, BURGOON MP, EDELMAN GM, CUNNINGHAM BA: Structure of a New Nervous Sys- tem Glycoprotein, Nr-CAM, and its Relationship to Subgroups of Neural Cell Adhesion Molecules. J Cell Biol 1991, 113:1399-1412. This paper describes the identification and characteriza- tion of an Ll-like glycoprotein in the chick. The impor- tance is twofold: first, it presents the first clear evidence for subgroups of immunoglobulin family members; and second, it shows that a second vertebrate cell adhe- sion molecule (CAM) can have its extracellular structure modified as a result of alternative splicing.

KINTNER C: Regulation of Embryonic Cell Adhesion by the Cadherin Cytoplasmic Domain. Cell 1992, 69:225-236. Cadherin mutants lacking most of the extracellular do- main are expressed in Xenopus embryos and shown to dramatically inhibit cell adhesion. The results are ex- plained by the mutant protein competing with the en- dogenous protein for binding to cytoskeletal elements. These studies complement previous studies, in that they demonstrate the importance of cytoskeletal interactions in the formation of stable adhesion between cells.

JONES FS, PREDIGER EA, BIT£NER DA, DE ROBERTIS EM, EDELMAN GM: Cell Adhesion Molecules as Tar- gets for H o x Genes: Neural Cell Adhesion Molecule Promoter Activity is Modulated by Contransfection with H o x -2.5 and -2.4. Proc Natl Acad Sci USA 1992, 89:2086-2090. The homeobox genes determine positional information during early development, and encode transcription fac- tors. Although very preliminary, this paper provides the first evidence that CAM genes might be subjected to reg- ulation by this class of transcription factor. Thus, CAMs could perhaps be the effector molecules that give cells their positional identity.

Membrane trafficking in neurons selected by' Eric Holtzman BENNETT MK, CALAKOS N, KREINER T, SCHELLER RH: Synaptic Vesicle Membrane Proteins Interact to Form a Multimeric Complex. J Cell Biol 1992, 116:761-775. Several species of synaptic vesicle proteins retain associ- ations with one another after detergent disruption of the

vesicle membrane. If such associations also prevail in vivo, the complexing of the proteins with one another could prove to be a key mechanism for establishing and maintaining the integrity of the vesicles' functional machinery during vesicle genesis and recycling.

BETZ WJ, BEWICK GS: Optical Analysis of Synaptic Vesicle Recycling at the Frog Neuromuscular Junc- tion. Science 1992, 255:200-203. Fluorescent styryl dyes permit visualization and analysis of the population behavior of recycling synaptic vesicles in living cells. The findings both confirm electron micro- scopic tracer analyses and extend results on time intervals and other phenomena that cannot readily be studied in fixed material.

Neuronal polarity selected by Ann Marie Craig, Mark Jareb and Gary Banker BAAS PW, PIENKOWSK[ TP, KOSLK KS: Processes In- duced by Tau Expression in Sf9 Cells have an Axon-like Microtubule Organization. J Cell Biol 1991, 115:1333-1344. Overexpression of tan induces the formation of micro- tubule bundles of uniform polarity orientation both in the cell body and in the processes of transfected Sf9 cells. The implication that MAPs can influence microtubule polarity orientation is quite novel.

FAIVRE-SARRAILH C, GENNARINI G, GORIDIS C, ROUGON G: F3 /F l l Cell Surface Molecule Expression in the De- veloping Mouse Cerebellum is Polarized at Synap- tic Sites and Within Grantfle Cells. J Neurosci 1992, 12:257-267. The GPI-anchored protein F3/F11 is axonal in gran- ule cells but uniformly distributed in Golgi neurons. This contradicts the 'epithelial-neuronal sorting hypothe- sis' and raises the possibility that different neurons sort proteins differently.

TORRE ER, STEWARD O: Demonstration of Local Protein Synthesis within Dendrites Using a New Cell Culture System that Permits the Isolation of Living Axons and Dendrites from their Cell Bodies. J Neurosci 1992, 12:762-772. When neurons are cultured on a membrane filter of ap- propriate pore size on top of a layer of Matrigel, ax- ons and dendrites grow through the filter and into the Matrigel so that they can be harvested free of cell bod- ies. Dendrites isolated by this novel method incorporate 3H-leucine into proteins.

544 (~) 1992 Current Biology