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M López-Ferber

Publications and source records attributed to M López-Ferber.

8 recordsLinked to original sources
PubMed2003

Annotation pattern of ESTs from Spodoptera frugiperda Sf9 cells and analysis of the ribosomal protein genes reveal insect-specific features and unexpectedly low codon usage bias.

MOTIVATION: A whole set of Expressed Sequence Tags (ESTs) from the Sf9 cell line of Spodoptera frugiperda is presented here for the first time. By this way we want to identify both conserved and specific genes of this pest species. We also expect from this analysis to find a class of protein sequences providing a tool to explore genomic features and phylogeny of Lepidoptera. RESULTS: The ESTs display both housekeeping as well as developmentally regulated genes, and a high percentage of sequences with unknown function. Among the identified ORFs, almost all ribosomal proteins (RPs) were found with high EST redundancy and hence sequence accuracy. The codon usage found among RP genes is in average surprisingly much less biased in Lepidoptera than in other organisms. Other Spodoptera genes also displayed a low bias, suggesting a general genome expression feature in this Lepidoptera. We also found that the L35A and L36 RP sequences, respectively, display 40 and 10 amino-acid insertions, both being present only in insects. Sequence analysis suggests that they are probably not subjected to a strong selective pressure and may be good phylogenetic markers for Lepidoptera. Most interestingly, the Lepidoptera sequences of 9 RP genes displayed a specific signature different from the canonical one. We conclude that the RP family allows valuable comparative genomics and phylogeny of Lepidoptera. AVAILABILITY: All EST sequence data are available from the private 'Spodo-Base' upon request.

Abstracting and Indexing↗
PubMed2000

Protein requirements for assembly of virus-like particles of Junonia coenia densovirus in insect cells.

The coding sequences of four overlapping polypeptides starting at four different in-frame AUG codons and co-terminating at the stop codon of the cap gene of Junonia coenia densovirus (JcDNV) were inserted under the control of the p10 promoter of Autographa californica nucleopolyhedrovirus (AcMNPV) to generate AcMNPV-VP1 (four polypeptides), AcMNPV-VP2 (three polypeptides), AcMNPV-VP3 (two polypeptides), and AcMNPV-VP4 (one polypeptide) recombinant viruses. In all cases, infection of Spodoptera frugiperda cells (Sf9) by each of the four recombinant viruses resulted in the production of virus-like particles (VLPs) 22-25 nm in diameter. The VLPs produced by the three recombinants AcMNPV-VP2, AcMNPV-VP3 and AcMNPV-VP4 were abundant and contained three, two and one polypeptides, respectively. VP4, the shortest polypeptide, thus appears to be sufficient for assembly of VLPs morphologically similar to those formed with two to four polypeptides. The ratio of VPs did not appear to be critical for assembly of the particles. The polypeptide starting at the first AUG immediately downstream from the p10 promoter was always the most abundantly expressed in infected cells, regardless of the construct. In contrast, plaque-purified AcMNPV-VP1 recombinants were unstable and produced less than one-twentieth of the VLPs produced by the others. All VP transcripts started at the TAAG late motif of the p10 promoter and had a poly(A) tail 14 nt downstream of a poly(A) addition signal located 98 nucleotides downstream of the common stop codon. No significant transcription initiation inside the cap sequence of AcMNPV-VP2, AcMNPV-VP3 and AcMNPV-PV4 was observed.

3' Untranslated Regions↗
PubMed1998

Temporal expression of the AcMNPV lef-4 gene and subcellular localization of the protein.

Autographa californica nucleopolyhedrovirus (AcMNPV) lef-4 gene [ORF 90; Ayres et al. (1994) Virology 202, 586-605] is involved in both late and very late gene expression [Passarelli and Miller (1993) Virology 197, 704-714]. The transcriptional properties of this gene have been analyzed. It is transcribed as a single 1.6-kb mRNA and transcripts were first detected 3 h postinfection (pi). The extremities of the transcript have been mapped by primer extension and 3' RACE-PCR to positions -56 from the translation start codon and +96 downstream of the stop codon. A rabbit polyclonal antiserum has been raised against an internal polypeptide of LEF-4. A 55-kDa protein was observed by Western blot analysis from 5 h pi. LEF-4 localizes preferentially in the nucleus of infected cells and is associated with the virogenic stroma.

Amino Acid Sequence↗
PubMed1998

The pnk/pnl gene (ORF 86) of Autographa californica nucleopolyhedrovirus is a non-essential, immediate early gene.

Autographa californica nucleopolyhedrovirus (AcMNPV) ORF 86, located within the HindIII C fragment, potentially encodes a protein which shares sequence similarity with two T4 bacteriophage gene products, RNA ligase and polynucleotide kinase. This AcMNPV gene has been designated pnk/pnl but has yet to be assigned a function in virus replication. It has been classified as an immediate early virus gene, since the promoter was active in uninfected insect cells and mRNA transcripts were detectable from 4 to 48 h post-infection and in the presence of cycloheximide or aphidicolin in virus-infected cells. The extremities of the transcript have been mapped by primer extension and 3' RACE-PCR to positions -18 from the translational start codon and +15 downstream of the stop codon. The function of pnk/pnl was investigated by producing a recombinant virus (Acdel86lacZ) with the coding region replaced with that of lacZ. This virus replicated normally in Spodoptera frugiperda (Sf 21) cells, indicating that pnk/pnl is not essential for propagation in these cells. Virus protein production in Acdel86lacZ-infected Sf 21 cells also appeared to be unaffected, with normal synthesis of the IE-1, GP64, VP39 and polyhedrin proteins. Shut-down of host protein synthesis was not abolished in recombinant infection. When other baculovirus genomes were examined for the presence of pnk/pnl by restriction enzyme digestion and PCR, a deletion was found in AcMNPV 1.2, Galleria mellonella NPV (GmMNPV) and Bombyx mori NPV (BmNPV), suggesting that in many isolates this gene has either never been acquired or has been lost during genome evolution. This is one of the first baculovirus immediate early genes that appears to be nonessential for virus survival.

Amino Acid Sequence↗
PubMed1998

Two key mutations in the host-range specificity domain of the p143 gene of Autographa californica nucleopolyhedrovirus are required to kill Bombyx mori larvae.

Autographa californica nucleopolyhedrovirus (AcMNPV) does not replicate in Bombyx mori cells (Bm5, BmN). We have shown previously that when a short DNA sequence within AcMNPV ORF95, which encodes the viral helicase P143, is replaced with the colinear region of B. mori nucleopolyhedrovirus (BmNPV), AcMNPV gains the ability to replicate in Bm5 cells. To determine the mutational events in the p143 gene required to allow AcMNPV replication in B. mori cells, AcMNPV recombinants produced in Sf9 cells were screened in vivo in B. mori larvae, which are more permissive to baculovirus infection than B. mori cell lines. Eight combinations of mutations were tested and characterization of viral DNA extracted from dead larvae showed that amino acid changes at position 564 and 577 are required to kill B. mori larvae.

Amino Acid Sequence↗
PubMed1992

Transmission of the hereditary S character in Drosophila simulans: effects of aging and temperature treatments.

The expression of the S character of Drosophila simulans associated to hereditary reovirus DSV is affected by the rearing temperature. The transmission of the S character and the consequences of the length of high temperature (28 degrees C) treatments on that transmission were investigated. Larvae treated at 28 degrees C from eclosion to imaginal emergence produce few S individuals in the offspring. The offspring of larvae treated between the 144th hr of development (middle of the pupal stage) and the imaginal emergence show variable levels of S phenotype expression. These levels appear to be related to the age and phenotype of their mothers. Those facts are discussed under the hypothesis of S character being caused by the hereditary reovirus Drosophila S virus.

Aging↗
PubMed1989

Drosophila S virus is a member of the Reoviridae family.

The S character of Drosophila simulans, the absence or malformation or both of bristles and other cuticular structures, was described by Comendador (Drosophila Inf. Serv. 55:26-28, 1980). Its characteristics (maternal transmission, low pathogenicity, and sensitivity to temperature) suggested the existence of a virus as the causative agent. Indeed, reoviruslike particles were found in subcuticular cells of S individuals, and its association with S phenotypic expression was shown. This virus was called Drosophila S virus (DSV) (C. Louis, M. López-Ferber, N. Plus, G. Kuhl, and S. Baker, J. Virol. 62:1266-1270, 1988). We report here the purification and analysis of some properties of DSV particles, the morphology (spherical, 60 nm in diameter with an electron dense central core and less dense shell) and genome composition (double-stranded RNA divided into segments), which classify DSV as a new member of the family Reoviridae.

Animals↗