Characterization of a transcriptionally active Tc1-like transposon in the microsporidian Nosema bombycis

2010 ◽  
Vol 55 (1) ◽  
Author(s):  
Jinshan Xu ◽  
Jie Luo ◽  
Bettina Debrunner-Vossbrinck ◽  
Xiaoyan Zhang ◽  
Hangdeng Liu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Transposable Element ◽  
Transcriptional Activity ◽  
Sequence Variation ◽  
Biological Control Agents ◽  
Functional Motif ◽  
Nosema Bombycis ◽  
Amino Acid Sequence Variation ◽  
Unique Clade

AbstractThe Tc1 transposable element has been found in a wide variety of organisms including vertebrates, insects and fungi but has not been previously reported in Microsporidia. In this study we characterize an intact DNA transposon (NbTc1) from the microsporidian Nosema bombycis. This transposable element encodes a 337 amino acid transposase sequence, which contains the D,D34E functional motif required for transposition. A Southern blot of N. bombycis DNA separated by pulsedesis shows that copies of the NbTc1 transposon are present on 10 of the 14 chromosomes of N. bombycis. Amino acid sequence variation among copies of the NbTc1 is low, suggesting a conserved function for this transposon within N. bombycis. Phylogenetic analysis indicates that NbTc1 is a new member of the Tc1 family lineage, quite distinct from all previously described Tc1 elements, including those from fungi, indicating that NbTc1 forms a unique clade of the Tc1 superfamily. However, the Tc1 transposon is too divergent to resolve the major phylogenetic relationships among these superfamilies. Reverse transcriptase PCR and Solexa sequencing suggest that NbTc1 possesses transcriptional activity. Considering the interest in Microsporidia as biological control agents, the NbTc1 transposon may be a useful vector for the efficient transfection of these important parasites into host species.

scholarly journals NRC-Interacting Factor 1 Is a Novel Cotransducer That Interacts with and Regulates the Activity of the Nuclear Hormone Receptor Coactivator NRC

2002 ◽  
Vol 22 (19) ◽  
pp. 6883-6894 ◽  
Author(s):  
Muktar A. Mahajan ◽  
Audrey Murray ◽  
Herbert H. Samuels
Keyword(s):  
Amino Acid ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Hormone Receptors ◽  
Nuclear Protein ◽  
Zinc Fingers ◽  
Nuclear Hormone Receptor ◽  
Coactivator Complex

ABSTRACT We previously reported the cloning and characterization of a novel nuclear hormone receptor transcriptional coactivator, which we refer to as NRC. NRC is a 2,063-amino-acid nuclear protein which contains a potent N-terminal activation domain and several C-terminal modules which interact with CBP and ligand-bound nuclear hormone receptors as well as c-Fos and c-Jun. In this study we sought to clone and identify novel factors that interact with NRC to modulate its transcriptional activity. Here we describe the cloning and characterization of a novel protein we refer to as NIF-1 (NRC-interacting factor 1). NIF-1 was cloned from rat pituitary and human cell lines and was found to interact in vivo and in vitro with NRC. NIF-1 is a 1,342-amino-acid nuclear protein containing a number of conserved domains, including six Cys-2/His-2 zinc fingers, an N-terminal stretch of acidic amino acids, and a C-terminal leucine zipper-like motif. Zinc fingers 1 to 3 are potential DNA-binding BED finger domains recently proposed to play a role in altering local chromatin architecture. We mapped the interaction domains of NRC and NIF-1. Although NIF-1 does not directly interact with nuclear receptors, it markedly enhances ligand-dependent transcriptional activation by nuclear hormone receptors in vivo as well as activation by c-Fos and c-Jun. These results, and the finding that NIF-1 interacts with NRC in vivo, suggest that NIF-1 functions to regulate transcriptional activation through NRC. We suggest that NIF-1, and factors which associate with coactivators but not receptors, be referred to as cotransducers, which act in vivo either as part of a coactivator complex or downstream of a coactivator complex to modulate transcriptional activity. Our findings suggest that NIF-1 may be a functional component of an NRC complex and acts as a regulator or cotransducer of NRC function.

scholarly journals Diversification of OmpA and OmpF of Yersinia ruckeri is independent of the underlying species phylogeny and evidence of virulence-related selection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael J. Ormsby ◽  
Robert L. Davies
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Atlantic Salmon ◽  
Sequence Variation ◽  
Housekeeping Genes ◽  
Housekeeping Gene ◽  
Yersinia Ruckeri ◽  
Amino Acid Sequence Variation

AbstractYersinia ruckeri is the causative agent of enteric redmouth disease (ERM) which causes economically significant losses in farmed salmonids, especially Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss, Walbaum). However, very little is known about the genetic relationships of disease-causing isolates in these two host species or about factors responsible for disease. Phylogenetic analyses of 16 representative isolates based on the nucleotide sequences of 19 housekeeping genes suggests that pathogenic Atlantic salmon and rainbow trout isolates represent distinct host-specific lineages. However, the apparent phylogenies of certain isolates has been influenced by horizontal gene transfer and recombinational exchange. Splits decomposition analysis demonstrated a net-like phylogeny based on the housekeeping genes, characteristic of recombination. Comparative analysis of the distribution of individual housekeeping gene alleles across the isolates demonstrated evidence of genomic mosaicism and recombinational exchange involving certain Atlantic salmon and rainbow trout isolates. Comparative nucleotide sequence analysis of the key outer membrane protein genes ompA and ompF revealed that the corresponding gene trees were both non-congruent with respect to the housekeeping gene phylogenies providing evidence that horizontal gene transfer has influenced the evolution of both these surface protein-encoding genes. Analysis of inferred amino acid sequence variation in OmpA identified a single variant, OmpA.1, that was present in serotype O1 and O8 isolates representing typical pathogenic strains in rainbow trout and Atlantic salmon, respectively. In particular, the sequence of surface-exposed loop 3 differed by seven amino acids to that of other Y. ruckeri isolates. These findings suggest that positive selection has likely influenced the presence of OmpA.1 in these isolates and that loop 3 may play an important role in virulence. Amino acid sequence variation of OmpF was greater than that of OmpA and was similarly restricted mainly to the surface-exposed loops. Two OmpF variants, OmpF.1 and OmpF.2, were associated with pathogenic rainbow trout and Atlantic salmon isolates, respectively. These OmpF proteins had very similar amino acid sequences suggesting that positive evolutionary pressure has also favoured the selection of these variants in pathogenic strains infecting both species.

scholarly journals Frequent Detection of Escape from Cytotoxic T-Lymphocyte Recognition in Perinatal Human Immunodeficiency Virus (HIV) Type 1 Transmission: the Ariel Project for the Prevention of Transmission of HIV from Mother to Infant

1999 ◽  
Vol 73 (5) ◽  
pp. 3975-3985 ◽  
Author(s):  
Cara C. Wilson ◽  
R. Clark Brown ◽  
Bette T. Korber ◽  
Barbara M. Wilkes ◽  
Debbie J. Ruhl ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Sequence Variation ◽  
Amino Acid Sequence Variation ◽  
Immunodeficiency Virus ◽  
Immunologic Factors ◽  
Hiv Type 1 ◽  
Hiv 1

ABSTRACT Host immunologic factors, including human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL), are thought to contribute to the control of HIV type 1 (HIV-1) replication and thus delay disease progression in infected individuals. Host immunologic factors are also likely to influence perinatal transmission of HIV-1 from infected mother to infant. In this study, the potential role of CTL in modulating HIV-1 transmission from mother to infant was examined in 11 HIV-1-infected mothers, 3 of whom transmitted virus to their offspring. Frequencies of HIV-1-specific human leukocyte antigen class I-restricted CTL responses and viral epitope amino acid sequence variation were determined in the mothers and their infected infants. Maternal HIV-1-specific CTL clones were derived from each of the HIV-1-infected pregnant women. Amino acid substitutions within the targeted CTL epitopes were more frequently identified in transmitting mothers than in nontransmitting mothers, and immune escape from CTL recognition was detected in all three transmitting mothers but in only one of eight nontransmitting mothers. The majority of viral sequences obtained from the HIV-1-infected infant blood samples were susceptible to maternal CTL. These findings demonstrate that epitope amino acid sequence variation and escape from CTL recognition occur more frequently in mothers that transmit HIV-1 to their infants than in those who do not. However, the transmitted virus can be a CTL susceptible form, suggesting inadequate in vivo immune control.

scholarly journals The Wzz (Cld) Protein in Escherichia coli: Amino Acid Sequence Variation Determines O-Antigen Chain Length Specificity

1998 ◽  
Vol 180 (10) ◽  
pp. 2670-2675 ◽  
Author(s):  
Agustin V. Franco ◽  
Dan Liu ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Chain Length ◽  
Sequence Variation ◽  
Length Distribution ◽  
Chain Length Distribution ◽  
E Coli ◽  
O Antigen ◽  
Amino Acid Sequence Variation

ABSTRACT The O antigen is a polymer with a repeated unit. The chain length in most Escherichia coli strains has a modal value of 10 to 18 O units, but other strains have higher or lower modal values.wzz (cld/rol) mutants have a random chain length distribution, showing that the modal distribution is determined by the Wzz protein. Cloned wzz genes from E. coli strains with short (7 to 16), intermediate (10 to 18), and long (16 to 25) modal chain lengths were transferred to a model system, and their effects on O111 antigen were studied. The O111 chain length closely resembled that of the parent strains. We present data based on the construction of chimeric wzz genes and site-directed mutagenesis of the wzz gene to show that the modal value of O-antigen chain length of E. coli O1, O2, O7, and O157 strains can be changed by specific amino acid substitutions in wzz. It is concluded that the O-antigen chain length heterogeneity in E. coli strains is the result of amino acid sequence variation of the Wzz protein.

Nucleotide and amino acid sequence variation in the L1 and E7 open reading frames of human papillomavirus type 6 and type 16

Virology ◽  
1991 ◽  
Vol 184 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Joseph P. Icenogle ◽  
Pushpa Sathya ◽  
Donna L. Miller ◽  
Ruth Ann Tucker ◽  
William Erawls
Keyword(s):  
Human Papillomavirus ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Sequence Variation ◽  
Open Reading Frames ◽  
Amino Acid Sequence Variation ◽  
Reading Frames

PURIFICATION AND PARTIAL CHEMICAL CHARACTERIZATION OF SHEEP NEUROPHYSIN

1973 ◽  
Vol 74 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Michel Chrétien ◽  
Claude Gilardeau
Keyword(s):  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Chemical Characterization ◽  
Terminal Amino Acid ◽  
Amino Acid Determination ◽  
Pituitary Glands ◽  
Terminal Amino ◽  
Partial Chemical ◽  
Acid Determination

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.

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