A system has been established allowing the rescue of replicating measles viruses (MVs) from cloned DNA. On one hand, plasmids were constructed from which MV antigenomic RNAs with the correct termini are transcribed by phage T7 RNA polymerase. On the other hand, helper cells derived from the human embryonic kidney 293 cell line were generated constitutively expressing T7 RNA polymerase together with MV nucleocapsid protein and phosphoprotein. Simultaneous transfection of the helper cells with the MV antigenomic plasmid and with a plasmid encoding the MV polymerase under direction of a T7 promoter led to formation of syncytia from which MVs were easily recovered. A genetic tag comprising three nucleotide changes was present in the progeny virus. As a first application of reverse genetics, a segment of 504 nucleotides from the 5′ non‐coding region of the fusion gene was deleted, leading to an MV variant whose replication behaviour in Vero cells was indistinguishable from that of the laboratory Edmonston B strain. Since no helper virus is involved, this system, in principle, should be applicable to the rescue of any member of the large virus order Mononegavirales, i.e. viruses with a nonsegmented negative‐strand RNA genome.

We propose the following principle to study pointed Hopf algebras, or more generally, Hopf algebras whose coradical is a Hopf subalgebra. Given such a Hopf algebra A, consider its coradical filtration and the associated graded coalgebra gr A. Then gr A is a graded Hopf algebra, since the coradical A of A is a Hopf 0 subalgebra. In addition, there is a projection : gr A ª A ; let R be the algebra of 0 coinvariants of . Then, by a result of Radford and Majid, R is a braided Hopf Ž . algebra and gr A is the bosonization or biproduct of R and A : gr A , R࠻A . 0 0The principle we propose to study A is first to study R, then to transfer the information to gr A via bosonization, and finally to lift to A. In this article, we apply this principle to the situation when R is the simplest braided Hopf algebra: a quantum linear space. As consequences of our technique, we obtain the classifica-3 Ž . tion of pointed Hopf algebras of order p p an odd prime over an algebraically closed field of characteristic zero; with the same hypothesis, the characterization of the pointed Hopf algebras whose coradical is abelian and has index p or p 2 ; and an infinite family of pointed, nonisomorphic, Hopf algebras of the same dimension. This last result gives a negative answer to a conjecture of I. Kaplansky. ᮊ 1998 Academic Press

We classify finite-dimensional complex Hopf algebras A which are pointed, that is, all of whose irreducible comodules are one-dimensional, and whose group of group-like elements G.A/ is abelian such that all prime divisors of the order of G.A/ are > 7. Since these Hopf algebras turn out to be deformations of a natural class of generalized small quantum groups, our result can be read as an axiomatic description of generalized small quantum groups.

Chronic inflammation is accompanied by impaired T-cell immunity. In the mouse, myeloid cell-associated arginase accounts for the suppression of immune reactivity in various models of tumor growth and chronic infections. Here we show that arginase I is liberated from human granulocytes, and very high activities accumulate extracellularly during purulent inflammatory reactions. Human granulocyte arginase induces a profound suppression of T-cell proliferation and cytokine synthesis. This T-cell phenotype is due to arginase-mediated depletion of arginine in the T-cell environment, which leads to CD3 chain down-regulation but does not alter T-cell viability. Our study therefore demonstrates that human granulocytes possess a previously unanticipated immunosuppressive effector function. Human granulocyte arginase is a promising pharmacologic target to reverse unwanted immunosuppression.

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SummaryTransport of nuclear-encoded precursor proteins into mitochondria includes proteolytic cleavage of aminoterminal targeting sequences in the mitochondrial matrix. We have isolated the processing activity from Neurospora crassa. The final preparation (enriched ca. lO,OOO-fold over cell extracts) consists of two proteins, the matrix processing peptidase (MPP, 57 kd) and a processing enhancing protein (PEP, 52 kd). The two components were isolated as monomers. PEP is about l&fold more abundant in mitochondria than MPP It is partly associated with the inner membrane, while MPP is soluble in the matrix. MPP alone has a low processing activity whereas PEP alone has no apparent activity. Upon recombining both, full processing activity is restored. Our data indicate that MPP contains the catalytic site and that PEP has an enhancing function. The mitochondrial processing enzyme appears to represent a new type of "signal peptidase,' different from the bacterial leader peptidase and the signal peptidase of the endoplasmic reticulum.

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