Two mRNAs that differ by two nontemplated nucleotides encode the amino coterminal proteins P and V of the paramyxovirus SV5

The "P" gene of the paramyxovirus SV5 encodes two known proteins, P (Mr approximately equal to 44,000) and V (Mr approximately equal to 24,000). The complete nucleotide sequence of the "P" gene has been obtained and is found to contain two open reading frames, neither of which is large enough to encode the P protein. We have shown that the P and V proteins are translated from two mRNAs that differ by the presence of two nontemplated G residues in the P mRNA. These two additional nucleotides convert the two open reading frames to one of 392 amino acids. The P and V proteins are amino coterminal and have 164 amino acids in common. The unique C terminus of V consists of a cysteine-rich region that resembles a cysteine-rich metal binding domain. An open reading frame that contains this cysteine-rich region exists in all other paramyxovirus "P" gene sequences examined, which suggests that it may have important biological significance.     

Fertility of the early postpartum, lactating domestic rabbit

Sixty-four crossbred primiparous lactating does each suckling six pups were allocated at random into four groups and were mated on either Day 1, 2, 3, or 4 post partum (where Day 0 = the day of parturition). They were subsequently killed on Day 10 post coitum (where Day 0 = the day of mating) to assess fertility. There were no significant differences between treatment groups in their mating response (97% overall), ovulation response (77% overall), implantation response (83% overall), implantation rate (8.7 overall), or preimplantation mortality rate (24% overall). Ovulation rate was significantly increased in does mated on Days 3 and 4 (13.3 and 13.1, respectively), compared with those mated on Day 1 (10.2, P<0.05) and Day 2 (9.6, P<0.01) post partum. From these results we conclude that fertility is high throughout the early postpartum period in the lactating rabbit.     

Molecular organisation of the quinic acid utilization (QUT) gene cluster in Aspergillus nidulans

Summary The functional integrity of the QUTB gene (encoding quinate dehydrogenase) has been confirmed by transformation of a qutB mutant strain. The DNA sequence of the contiguous genes QUTD (quinate permease), QUTB and QUTG (function unknown) has been determined and analysed, together with that of QUTE (catabolic 3-dehydroquinase). The QUTB sequence shows significant homology with the shikimate dehydrogenase function of the complex AROM locus of Aspergillus nidulans, and with the QA-3 quinate dehydrogenase and QA-1S (repressor) genes of Neurospora crassa. The QUTD gene shows strong homology with the N. crassa QA-Y gene and QUTG with the QA-X gene. QUTD, QUTB, and QUTG, QUTE form two pairs of divergently transcribed genes, and conserved sequence motifs identified in the two common 5 non-coding regions show significant homology with UAS _GAL and UAS _QA sequences of the Saccharomyces cerevisiae and N. crassa Gal and QA systems. In addition, conserved 5 sequences homologous to the mammalian CAAT box are noted and a previously unreported conserved 22 nucleotide motif is presented.     

Syringe exchange schemes for drug users in England and Scotland

In 1987 experimental schemes for distributing injecting equipment to intravenous drug users to help prevent the spread of the human immunodeficiency virus were started by the government. After six months the schemes were found to have been reasonably successful in attracting clients but were less successful in keeping them. It has been shown that equipment can be distributed to drug users on an exchange basis. Many of the clients who were attracted to these schemes had had no treatment or other help for their drug problems.     

Quantification by laser scan microscopy of intracellular doxorubicin distribution.

Changes in intracellular drug localization accompany doxorubicin resistance in multidrug resistant tumor cells. The purpose of this study was to develop a method to quantify these changes and so detect different levels of resistance. Tumor cells were incubated with the fluorescent anthracycline doxorubicin (excitation at 480 nm; emission maximum at 560-590 nm) and were quantified using laser scanning microscopy. The fluorescent mode was used to record the intracellular drug distribution, whereas the absorption mode was used to define the nuclear and cytoplasmic boundaries. The cell compartments were delineated interactively on an image processing system and the ratio nuclear fluorescence/cytoplasmic fluorescence (N/C ratio) was determined. N/C ratios were: 1.8 in the Chinese hamster ovarian cell line AUXB1 and 0.1 in its MDR subline CHRC5; 3.8 in the human squamous lung cancer cell line SW-1573 and 1.8 and 0.4 in its MDR sublines SW-1573/2R120 and SW-1573/2R160, respectively; and 3.6 in the human myeloma cell line 8226/S and 2.1 and 1.0 in its MDR sublines 8226/Dox4 and 8226/Dox40, respectively. The doxorubicin distribution was independent of the doxorubicin concentration within a range from 1-32 microM. Furthermore, the progressive mean of the nuclear/cytoplasmic doxorubicin fluorescence ratio showed that a minimal sample size of 30 cells is necessary for reliable results. The results of two independent assessments showed a high reproducibility (r = 0.97). Thus, with the method described in this paper, it is possible to detect relatively low levels of doxorubicin resistance (factor 8).     

A second gene (qutH) within the Aspergillus nidulans-quinic-acid utilisation gene cluster encodes a protein with a putative zinc-cluster motif.

A sequence of 3299 nt, contiguous with the previously sequenced quinate permease-encoding (qutD) gene and encompassing the dehydroshikimate dehydratase-encoding (qutC) gene, has been determined. Northern-blot analysis detected (i) a quinate-inducible mRNA of the expected size for the qutC gene, and (ii) a quinate-inducible mRNA of 1.45 kb divergently transcribed away from qutC towards qutD. Computer-aided sequence analysis identified an ORF of 1047 nt corresponding to the qutC gene encoding dehydroshikimate dehydratase. In addition, a genetically uncharacterized 1188-nt gene, designated qutH and containing a putative intron of 61 nt, was identified between qutC and qutD. The inferred protein sequence encoded by qutH contains a putative 'zinc cluster' motif and has a low (16%) but significant similarity with the DNA-directed DNA polymerase of hepatitis B virus. The results are interpreted as being consistent with the view that the qutH gene encodes a DNA-binding protein, possibly involved in the regulation of genes essential for the utilisation of protocatechuic acid.     

Diversity of coding strategies in influenza viruses.

Influenza viruses have exploited a variety of strategies to increase their genome coding capacities. These include unspliced, spliced, alternatively spliced and bicistronic mRNAs, translation from overlapping reading frames and a coupled stop-start translation of tandem cistrons.