Learn More
Extracellular matrix (ECM) glycoproteins regulate neuronal development and axonal growth. In this paper, the ECM glycoprotein vitronectin was identified and localized in the embryonic chick neuroretina. To identify potentially important neurite outgrowth-promoting molecules, responses of embryonic chick retinal neurons to vitronectin and thrombospondin,(More)
Evidence that pre-mRNA processing events are temporally and, in some cases, mechanistically coupled to transcription has led to the proposal that RNA polymerase II (Pol II) recruits pre-mRNA splicing factors to active genes. Here we address two key questions raised by this proposal: (i) whether the U1 snRNP, which binds to the 5' splice site of each intron,(More)
Cell attachment and neurite outgrowth by embryonic neural retinal cells were measured in separate quantitative assays to define differences in substrate preference and to demonstrate developmentally regulated changes in cellular response to different extracellular matrix glycoproteins. Cells attached to laminin, fibronectin, and collagen IV in a(More)
Coupling between transcription and pre-mRNA splicing is a key regulatory mechanism in gene expression. Here, we investigate cotranscriptional spliceosome assembly in yeast, using in vivo crosslinking to determine the distribution of spliceosome components along intron-containing genes. Accumulation of the U1, U2, and U5 small nuclear ribonucleoprotein(More)
Spliceosomal small nuclear ribonucleoproteins (snRNPs), comprised of small nuclear RNAs (snRNAs) in complex with snRNP-specific proteins, are essential for pre-mRNA splicing. Coilin is not a snRNP protein but concentrates snRNPs and their assembly intermediates in Cajal bodies (CBs). Here we show that depletion of coilin in zebrafish embryos leads to CB(More)
Integrins are a family of alpha beta heterodimeric receptors that mediate cell-cell and cell-substratum interactions. Integrin binding to extracellular ligands regulates cell adhesion, shape, motility, intracellular signalling and gene expression. Mechanisms that regulate integrin function are, therefore, central to the participation of integrins in a(More)
Pre-mRNA splicing is catalyzed by the spliceosome, which can assemble on pre-mRNA cotranscriptionally. However, whether splicing generally occurs during transcription has not been addressed. Indeed, splicing catalysis is expected to occur posttranscriptionally in yeast, where the shortness of terminal exons should leave insufficient time for splicing. Here,(More)
Retinal ganglion neurons extend axons that grow along astroglial cell surfaces in the developing optic pathway. To identify the molecules that may mediate axon extension in vivo, antibodies to neuronal cell surface proteins were tested for their effects on neurite outgrowth by embryonic chick retinal neurons cultured on astrocyte monolayers. Neurite(More)
The Cajal body (CB) is an evolutionarily conserved nuclear subcompartment, enriched in components of the RNA processing machinery. The composition and dynamics of CBs in cells of living organisms is not well understood. Here we establish the zebrafish embryo as a model system to investigate the properties of CBs during rapid growth and cell division, taking(More)
The spliceosomal small nuclear RNAs (snRNAs) are distributed throughout the nucleoplasm and concentrated in nuclear inclusions termed Cajal bodies (CBs). A role for CBs in the metabolism of snRNPs has been proposed but is not well understood. The SART3/p110 protein interacts transiently with the U6 and U4/U6 snRNPs and promotes the reassembly of U4/U6(More)