Alternative processing of the RNA transcribed from the calcitonin gene appears to result in the production of a messenger RNA in neural tissue distinct from that in thyroidal 'C' cells. The thyroid mRNA encodes a precursor to the hormone calcitonin whereas that in neural tissues generates a novel neuropeptide, referred to as calcitonin gene-related peptide (CGRP). The distribution of CGRP-producing cells and pathways in the brain and other tissues suggests functions for the peptide in nociception, ingestive behaviour and modulation of the autonomic and endocrine systems. The approach described here permits the application of recombinant DNA technology to analyses of complex neurobiological systems in the absence of prior structural or biological information.

Proteins of the Bcl-2 family are intracellular membrane-associated proteins that regulate programmed cell death (apoptosis) either positively or negatively by as yet unknown mechanisms. Bax, a pro-apoptotic member of the Bcl-2 family, was shown to form channels in lipid membranes. Bax triggered the release of liposome-encapsulated carboxyfluorescein at both neutral and acidic pH. At physiological pH, release could be blocked by Bcl-2. Bcl-2, in contrast, triggered carboxyfluorescein release at acidic pH only. In planar lipid bilayers, Bax formed pH- and voltage-dependent ion-conducting channels. Thus, the pro-apoptotic effects of Bax may be elicited through an intrinsic pore-forming activity that can be antagonized by Bcl-2.

Different chemical methods used to attach oligonucleotides by their 5'-end on a glass surface were tested in the framework of solid phase PCR where surface-bound instead of freely-diffusing primers are used to amplify DNA. Each method was first evaluated for its capacity to provide a high surface coverage of oligonucleotides essentially attached via a 5'-specific linkage that satisfyingly withstands PCR conditions and leaves the 3'-ends available for DNA polymerase activity. The best results were obtained with 5'-thiol-modified oligonucleotides attached to amino-silanised glass slides using a heterobifunctional cross-linker reagent. It was then demonstrated that the primers bound to the glass surface using the optimal chemistry can be involved in attaching and amplifying DNA molecules present in the reaction mix in the absence of freely-diffusing primers. Two distinct amplification processes called interfacial and surface amplification have been observed and characterised. The newly synthesised DNA can be detected and quantified by radioactive and fluorescent hybridisation assays. These new surface amplification processes are seen as an interesting approach for attachment of DNA molecules by their 5'-end on a solid support and can be used as an alternative route for producing DNA chips for genomic studies.

Recombinant murine GM-CSF produced in Escherichia coli was purified to homogeneity and tested in parallel with purified native GM-CSF. Both recombinant and native GM-CSF stimulated granulocyte and/or macrophage colony formation by adult and fetal mouse progenitor cells, and with adult marrow cells the specific activity of the recombinant GM-CSF (25 X 10(8) U/mg) was similar to that of the native form (15 X 10(8) U/mg). At high concentrations (greater than 200 U/ml), both forms of GM-CSF also stimulated eosinophil colony formation by adult marrow cells and, at very high concentrations (greater than 800 U/ml), megakaryocyte and some erythroid and mixed-erythroid colony formation. Recombinant GM-CSF was as effective in stimulating the proliferation of the GM-CSF-dependent cell line FD as the native molecule. Both recombinant and native GM-CSF were able to induce partial differentiation in colonies of WEHI-3B myeloid leukemic cells. Recombinant GM-CSF competed effectively for the binding of 125I-labeled native GM-CSF to hemopoietic cells, and antiserum to recombinant GM-CSF also neutralized the biological activity of native GM-CSF. The bacterially synthesized GM-CSF was a slightly more effective stimulus for megakaryocyte colony formation than the native molecule. The demonstration that purified bacterially synthesized GM-CSF is biologically active in vitro now permits studies to be undertaken on the in vivo effects of this material.

Two mRNAs generated as a consequence of alternative RNA processing events in expression of the human calcitonin gene encode the protein precursors of either calcitonin or calcitonin gene-related peptide (CGRP). Both calcitonin and CGRP RNAs and their encoded peptide products are expressed in the human pituitary and in medullary thyroid tumors. On the basis of sequence comparison, it is suggested that both the calcitonin and CGRP exons arose from a common primordial sequence, suggesting that duplication and rearrangement events are responsible for the generation of this complex transcription unit.We have documented that the rat calcitonin gene can generate two mRNAs encoding discrete polypeptide products as a result of tissue-specific alternative RNA processing (1)(2)(3)(4). The products of these RNAs are the precursors to the calcium-regulating hormone, calcitonin, and to two other peptides in the thyroidal "C" cell and are the precursors to a novel neuropeptide and hormone referred to as CGRP (calcitonin gene-related peptide) and two other peptides. Histochemical analysis with antisera against a synthetic CGRP fragment and nuclease S1 mapping have demonstrated CGRP expression and localization in the brain and other tissues (4). On the basis of its anatomical distribution and initial physiological studies with chemically synthesized peptide, CGRP is suggested to exert regulatory effects on nociception, ingestive behavior, and cardiovascular homeostasis (4, 5). In addition to its localization in neural tissue, CGRP also is produced in the endocrine system (including thyroid "C" cells, adrenal chromaffin cells, and bronchiolar cells) and is distributed widely in sensory nerves and in nerves supplying vasculature in many other organs (e.g., skin, genitourinary system). The molecular basis for the alternative RNA processing appears to be selective utilization of calcitonin-or CGRP-specific poly(A) sites present in the transcription unit associated with different patterns of exon splicing and ligation reactions (6). Similar RNA processing events appear to operate in expression of other eukaryotic genes (e.g., refs. 7-13) and in a number of animal DNA viruses (14-17). Alternative patterns of RNA splicing in association with the use of a single poly(A) site are also observed in expression of a number of genes, including the rat calcitonin/CGRP gene (6,(18)(19)(20)(21)(22).In this manuscript we report that the human calcitonin/CGRP gene can generate two mRNAs encoding the precursors of calcitonin and CGRP as a result of alternative RNA processing events, documenting the operation of this type of post-transcriptional regulation in the human neuroendocrine system. The structure of the human CGRP precursor predicts the excision of a 37-amino acid peptide differing in 4 amino acids from the primary sequence of rat CGRP. The predicted peptide is identical with the structure of a peptide from human medullary thyroid tumors in novel fast-atom-bombardment mass spectometry (23). Both RNA and peptide products of the human...