A full-length cDNA clone of a previously unidentified serine protease, myelencephalon-specific protease (MSP), has been isolated by using a PCR cloning strategy and has been shown to be expressed in a nervous system and spinal cord-specific pattern. Sequence analysis demonstrated that MSP is most similar in sequence to neuropsin, trypsin, and tissue kallikrein and is predicted to have trypsin-like substrate specificity. MSP mRNA was found to be ϳ10-fold greater in the CNS of the rat and human, as compared with most peripheral tissues, and within the CNS was found to be highest by a factor of four in the medulla oblongata and spinal cord. Levels of mRNA encoding tissue plasminogen activator (tPA) also were elevated in the spinal cord but were more widespread in peripheral tissues as compared with MSP.In the adult rat lumbosacral spinal cord, in situ localization of MSP mRNA demonstrated 2-fold higher levels in the white, as compared with the gray, matter. MSP mRNA expression was shown to increase 3-fold in the white matter and 1.5-fold in the gray laminae at 72 hr after intraperitoneal injection of the AMPA/ kainate glutamate receptor-specific agonist, kainic acid (KA). MSP mRNA remained elevated in the ventral gray matter, including expression associated with the motor neurons of lamina IX, at 7 d after the initial excitotoxic insult. Together, these observations indicate that MSP is in a position to play a fundamental role in normal homeostasis and in the response of the spinal cord to injury.

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We have used the polyrnerase chain reaction (PCR) to amplify and clone coding sequences of the mature region of brain-derived neurotrophic factor (BDNF) from monkey, rat, chicken and XenopuF genomic DNA. Consistent with previous reports, the predicted amino acid sequences obtained in this manner from monkey and rat were identi c?J !o other mammalian BDNF sequences. 'The chicken and Xenopus BDNF sequences arc also highly conserved, but contain 7 and 8 amix acid substitutions, respectively, compared to mammalian BDNF. Comparison of these sequences with the homologous NGF and NT3 coding .r..'ions provides further insight into amino acid residues that may be responsible for the differenl receptor specificities of these factors.

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