The gene encoding bovine brain-derived neurotrophic factor (BDNF).

We present the nucleotide (nt) sequence for the cDNA encoding bovine brain-derived neurotrophic factor (BDNF). The nt and peptide sequences were compared to those of other BDNF genes from other species.

Expression of neurotrophins and their receptors in the developing and adult rat adrenal gland.

We have studied the postnatal expression of neurotrophins, their cognate high-affinity trk receptors and the low-affinity NGF receptor (p75LNGFR) in the rat adrenal gland using RT-PCR. Neurotrophin mRNAs were detectable during the whole postnatal period. Strongest signals were obtained for BDNF and NT4/5. Expression of trkA, trkB, trkC and p75LNGFR was found at all ages studied. Signals for trkA were highest in the adult adrenal medulla, whereas signals for p75LNGFR were highest in the adult adrenal cortex. Cur data suggest still largely enigmatic roles for neurotrophins in functions of the adrenal medulla and possibly also the cortex.

TGF-beta rescues target-deprived preganglionic sympathetic neurons in the spinal cord.

Transforming growth factors beta (TGF-beta), a family of pleiotropic cytokines, are widely distributed in the developing and adult nervous system. In order to further determine the neural functions of TGF-beta, we have localized the TGF-beta isoforms 1, 2 and 3 in the adult rat adrenal medulla and studied the neuroprotective capacity of one representative family member, TGF-beta 2, for those spinal cord neurons which innervate adrenal chromaffin cells and which die after destruction of the adrenal medulla. Unilateral electrothermal destruction of the adrenal medulla led to the disappearance of 25% of sympathetic preganglionic neurons, which are located in the intermediolateral (IML) column of thoracic spinal cord segments 7-10 and can be selectively marked by NADPH-diaphorase. The neurons which disappeared following adrenomedullectomy constitute the full set of neurons that innervate the adrenal medulla. Implantation of gelfoam soaked with 0.5 micrograms TGF-beta 2 into the adrenal wound cavity rescued all spinal cord neurons in the IML ipsilaterally to the lesioned side. Cytochrome c was not effective. Injections of [125I]TGF-beta 2 into the adrenal medulla did not result in retrograde transport and subsequent labelling of spinal cord neurons, suggesting that TGF-beta may exert its neuroprotective actions by indirect mechanisms. TGF-beta applied to cultured adrenocortical cells did not overtly increase the amount of mRNA for fibroblast growth factor-2, an established trophic molecule for sympathetic preganglionic spinal cord neurons. The mechanisms by which TGF-beta exerts its neurotrophic effect are therefore unclear. Even so, our data provide the first evidence that TGF-beta may play an important role in vivo in the control of maintenance of a population of spinal cord neurons.

Expression of interleukin-6 (IL-6) and IL-6 receptor mRNAs in rat adrenal medulla.

Using in situ hybridization and reverse transcription combined with the polymerase chain reaction (RT-PCR) we have studied the expression and developmental regulation of interleukin-6 (IL-6) and its receptor mRNAs in rat adrenal medulla. Labeling for both transcripts was much more intense over the adrenal medulla than over cortical regions at postnatal day 70. Levels of mRNAs of both genes measured by RT-PCR increased from birth to adulthood. In vitro survival and neurite growth of chromaffin cells from early postnatal rats were not affected by IL-6. Even so, the presence and developmental regulation of IL-6 and its receptor are consistent with a possible auto- or paracrine role of IL-6 in rat adrenal medulla.

Trophic factors from chromaffin granules promote survival of peripheral and central nervous system neurons.

Chromaffin cells of the adrenal medulla were used to study the release of neurotrophic factors operationally defined by their capacity to promote the in vitro survival of embryonic neurons from the peripheral and central nervous system. Chromaffin cells are closely related to sympathetic neurons in terms of their transmitters and specific proteins and, like sympathetic neurons, receive preganglionic cholinergic, aminergic and peptidergic neuronal inputs. The issue of whether chromaffin cells store and secrete neurotrophic factors is therefore pertinent to the question whether trophic mechanisms may be involved in neuronal interactions and what modes of secretion are employed to liberate neurotrophic factors from neurons. Cell culture media conditioned by purified bovine chromaffin cells supported several neuron populations in vitro. Stimulation of the chromaffin cells with the cholinergic agonist carbachol (10(-4) M) increased in parallel the output of neurotrophic factor activity (assayed on chick ciliary ganglionic neurons) as well as two components specifically located in chromaffin granules, chromogranin A and catecholamines. The release of all three components was partially blocked by the Ca2+ channel blocker verapamil (10(-5) M), suggesting co-storage and -release of neurotrophic factors, chromogranin A and catecholamines in/from chromaffin granules. Neurotrophic factor activity for ciliary ganglionic neurons accumulating in the medium of unstimulated chromaffin cells decreased with time, and so did catecholamines. In contrast, amounts of neurotrophic factors and catecholamines released by challenging cells with carbachol did not significantly decline up to 62 h. The neurotrophic factor activity tested on chick ciliary, sensory and spinal cord neurons as well as on rat hippocampal neurons was heat- and trypsin-labile and could not be blocked by polyclonal antibodies against bovine nerve growth factor and the chromogranin A, B, and C. Defined fragments of chromogranin A and pancreastatin were devoid of neurotrophic activity. Our results suggest the presence of one or several neurotrophic factors in chromaffin granules, which can be released by exocytosis and may be potentially relevant for the maintenance of neurons innervating the adrenal medulla.

Three alpha-amylase genes of Aspergillus oryzae exhibit identical intron-exon organization.

We have cloned three genes (amy1, amy2 and amy3) encoding alpha-amylase in the filamentous fungus Aspergillus oryzae. The established overall sequences have a very high degree of homology, showing divergences mainly in the 3'-untranslated regions. The positions and the sequences of the eight introns were found to be absolutely identical in the three genes. The sequence analysis of the 5'-regions revealed presumptive TATA, CAAT and GC boxes. Primer extension analysis was performed to determine the transcription start. We were able to detect mRNAs from amy1 and amy3 but not from amy2 with gene-specific oligonucleotide probes complementary to the 3'-noncoding regions.