. Chem. 258, 4331 (1983)]. The enzyme was measured in 4M urea extracts of skin samples [H. M. Kagan and K. A. Sullivan, Methods Enzymol. 82A, 637 (1982)] by an enzyme-linked immunoassay. The net accumulation oflysyl oxidase in the extracellular matrix of dorsal skin (in micrograms per gram ± SEM) was reduced from 500± 123 to 146 ± 55 by week 8 (P < 0.01; for two replicates, n = 4 to 6 each). The lysyl oxidase antibody preparation and the enzyme-linked inumunoassay were done as described by H. Bode and H. Stegeman [J. Immunol. Methods 72,421 (1984) Carroll and B. D. Stallar [J. Biol. Chem. 258, 24 (1983)]. A preliminary report on the characterization of lysyl oxidase and its quantitation by enzyme-linked inmmunosorbent assay (ELISA) has been published by D. Tinker, N. Romero, and R. B.] and S. B.

Interferon-inducible membrane proteins of approximately 17 kDa have been suggested to play a role in the antiproliferative activity of interferons based on (1) their pattern of induction in interferon-sensitive and -resistant cell lines and (2) the ability of a membrane fraction enriched in 17-kDa proteins to inhibit cell growth. To gain insight into the nature of the proteins that mediate the antiproliferative activity of interferons, a monoclonal antibody, 13A5, was generated that reacted specifically with a 17-kDa interferon-inducible cell surface protein. The expression pattern of this 17-kDa protein by human cell lines correlated with sensitivity to the antiproliferative activity of interferons. To obtain information regarding the structure of this protein, the 13A5 antibody was used to screen COS cells transfected with a human cDNA expression library. Sequence analysis of a full-length cDNA clone revealed identity with the 9 -27 cDNA, previously isolated on the basis of its interferon inducibility by differential screening. In addition, the 17-kDa protein encoded by the 9 -27 gene was shown to be identical to the Leu-13 antigen. Leu-13 was previously identified as a 16-kDa interferoninducible protein in leukocytes and endothelial cells and is a component of a multimeric complex involved in the transduction of antiproliferative and homotypic adhesion signals. These results suggest a novel level of cellular regulation by interferons involving a membrane protein, encoded by the interferon-inducible 9 -27 gene, which associates with other proteins at the cell surface, forming a complex relaying growth inhibitory and aggregation signals.

The sequence of several cDNAs encoding the amyloid protein precursor showed that two polyadenylation sites of the mRNA are utilized; RNA blot analysis with different riboprobes indicated that this explains the difference between the two major 3.2 and 3.4 kb mRNAs found in the human brain. These two mRNAs, which contain the whole sequence of the natural molecules, were synthesized by in vitro transcription and translated in Xenopus oocytes. The long mRNA using the second polyadenylation site produced more protein than the short mRNA. The sequence contained within the two polyadenylation sites used in the 3′ untranslated region of the amyloid protein precursor mRNA was also able to increase the production of the chicken lysozyme or the chloramphenicol acetyl transferase, as demonstrated by in vivo translation of different chimeric mRNAs obtained by in vitro transcription. This difference in protein production was also observed when chimeric cDNA constructs were transfected into Chinese hamster ovary cells. Since long mRNAs are not more stable than short mRNAs, the sequence contained within the two polyadenylation sites of the amyloid protein precursor mRNA increases the translation.

Elements of the olfactory pathway, such as receptors, receptor-desensitization machinery, and cyclic nucleotide-gated channels, are expressed in male germ cells. Here we report the expression, in rat testis, of both adenylyl cyclase type 3 (AC3) and the olfactory G protein subunit, G Kolf . Both are expressed in the same sub-population of germ cells, pachytene spermatocytes to spermatids, and in residual bodies. Neither AC3 nor G Kolf was found in Sertoli or in peritubular cells, as shown by Western blotting and immunocytochemical analyses. It thus appears that male germ cells contain all the elements of the signaling cascade present in olfactory cells.z 1998 Federation of European Biochemical Societies.

In Arabidopsis thaliana, the tef1 box is a cis-acting promoter element of the EF-1 alpha A1 gene involved in the activation of transcription in meristematic tissues. The initiation of root calli in transgenic Arabidopsis by 2,4-D shows that the tef1-dependent expression of the GUS reporter gene is not restricted to meristematic regions but involves all of the cycling cells. Hybridization experiments conducted using Arabidopsis cDNA clones organized in a dense array on filters, and cDNA probes prepared from cells in various states of growth, or blocked at different steps of the cell cycle, indicate that the enhanced expression of EF-1 alpha genes occurs in cycling cells at the point of entry into the cell cycle and remains constant during transit through the cycle. The analysis of several promoters of genes, other than EF-1 alpha, which are overexpressed in growing cells and involved in the processes of translation or redox regulation, reveals the presence of sequences showing partial homologies with the tef1 box. The Arabidopsis ribosomal gene srp18 and the tobacco gene thioh2, encoding a thioredoxin h, contain such sequences. Gel retardation experiments suggest that these sequences are targets for the same proteins as those that interact with the tef1 box of the Arabidopsis EF-1 alpha A1 gene. In transfected Arabidopsis protoplasts, the putative tef1 sequence thioh2 partially restores the activity of a tef1 box-less EF-1 alpha A1 promoter. These data demonstrate that the tef1 box is a ubiquitous cis-acting element involved in the transcriptional activation of plant genes that are overexpressed in cycling cells.(ABSTRACT TRUNCATED AT 250 WORDS)