No abstract

Olig family is a novel sub-family of basic helix-loop-helix transcription factors recently identified. Olig1 and Olig2 were first reported to promote oligodendrocyte differentiation, and later Olig2 was reported to be involved in motoneuron specification as well. Olig3 was isolated as a third member of Olig family, but its precise expression pattern is poorly understood. Here, we describe detailed Olig3 expression analyses in the neural tube of embryonic mice. Olig3 was first detected in the dorsal neural tube from the midbrain/hindbrain boundary to the spinal cord. In E11.5 spinal cord, Olig3 was transiently expressed in the lateral margin of the subventricular zone as three ventral clusters at the level of the p3, p2 and p0 domains, as well as in the dorsal neural tube. Olig3 was co-expressed with Nkx2.2 in the lateral margin of the p3 domain. In forebrain, Olig3 was expressed in the dorsal thalamus while Olig2 was complementarily expressed in the ventral thalamus with an adjacent boundary at E12.5. Olig3 is specifically and transiently expressed in different types of progenitors of embryonic central nervous system and then disappears in the course of development.

High endothelial venule (HEV) cells support lymphocyte migration from the peripheral blood into secondary lymphoid tissues. Using gene expression profiling of mucosal addressin cell adhesion molecule-1+ mesenteric lymph node HEV cells by quantitative 3′-cDNA collection, we have identified a leucine-rich protein, named leucine-rich HEV glycoprotein (LRHG) that is selectively expressed in these cells. Northern blot analysis revealed that LRHG mRNA is ∼1.3 kb and is expressed in lymph nodes, liver, and heart. In situ hybridization analysis demonstrated that the mRNA expression in lymph nodes is strictly restricted to the HEV cells, and immunofluorescence analysis with polyclonal Abs against LRHG indicated that the LRHG protein is localized mainly to HEV cells and possibly to some lymphoid cells surrounding the HEVs. LRHG cDNA encodes a 342-aa protein containing 8 tandem leucine-rich repeats of 24 aa each and has high homology to human leucine-rich α2-glycoprotein. Similar to some other leucine-rich repeat protein family members, LRHG can bind extracellular matrix proteins that are expressed on the basal lamina of HEVs, such as fibronectin, collagen IV, and laminin. In addition, LRHG binds TGF-β. These results suggest that LRHG is likely to be multifunctional in that it may capture TGF-β and/or other related humoral factors to modulate cell adhesion locally and may also be involved in the adhesion of HEV cells to the surrounding basal lamina.

Gene expression data are exponentially accumulating; thus, the functional annotation of such sequence data from metadata is urgently required. However, life scientists have difficulty utilizing the available data due to its sheer magnitude and complicated access. We have developed a web tool for browsing reference gene expression pattern of mammalian tissues and cell lines measured using different methods, which should facilitate the reuse of the precious data archived in several public databases. The web tool is called Reference Expression dataset (RefEx), and RefEx allows users to search by the gene name, various types of IDs, chromosomal regions in genetic maps, gene family based on InterPro, gene expression patterns, or biological categories based on Gene Ontology. RefEx also provides information about genes with tissue-specific expression, and the relative gene expression values are shown as choropleth maps on 3D human body images from BodyParts3D. Combined with the newly incorporated Functional Annotation of Mammals (FANTOM) dataset, RefEx provides insight regarding the functional interpretation of unfamiliar genes. RefEx is publicly available at http://refex.dbcls.jp/.