Nucleoid-associated proteins in Crenarchaea

2011 ◽  
Vol 39 (1) ◽  
pp. 116-121 ◽  
Author(s):  
Rosalie P.C. Driessen ◽  
Remus Th. Dame

Architectural proteins play an important role in compacting and organizing the chromosomal DNA in all three kingdoms of life (Eukarya, Bacteria and Archaea). These proteins are generally not conserved at the amino acid sequence level, but the mechanisms by which they modulate the genome do seem to be functionally conserved across kingdoms. On a generic level, architectural proteins can be classified based on their structural effect as DNA benders, DNA bridgers or DNA wrappers. Although chromatin organization in archaea has not been studied extensively, quite a number of architectural proteins have been identified. In the present paper, we summarize the knowledge currently available on these proteins in Crenarchaea. By the type of architectural proteins available, the crenarchaeal nucleoid shows similarities with that of Bacteria. It relies on the action of a large set of small, abundant and generally basic proteins to compact and organize their genome and to modulate its activity.

1988 ◽  
Vol 8 (3) ◽  
pp. 1282-1289
Author(s):  
W Haggren ◽  
D Kolodrubetz

The high-mobility-group (HMG) proteins, a group of nonhistone chromatin-associated proteins, have been extensively characterized in higher eucaryotic cells. To test the biological function of an HMG protein, we have cloned and mutagenized a gene encoding an HMG-like protein from the yeast Saccharomyces cerevisiae. A yeast genomic DNA library was screened with an oligonucleotide designed to hybridize to any yeast gene containing an amino acid sequence conserved in several higher eucaryotic HMG proteins. DNA sequencing and Northern (RNA) blot analysis revealed that one gene, called ACP2 (acidic protein 2), synthesizes a poly(A)+ RNA in S. cerevisiae which encodes a 27,000-molecular-weight protein whose amino acid sequence is homologous to those of calf HMG1 and HMG2 and trout HMGT proteins. Standard procedures were used to construct a diploid yeast strain in which one copy of the ACP2 gene was mutated by replacement with the URA3 gene. When this diploid was sporulated and dissected, only half of the spores were viable. About half of the nonviable spores proceeded through two or three cell divisions and then stopped dividing; the rest did not germinate at all. None of the viable spores contained the mutant ACP2 gene, thus proving that the protein encoded by ACP2 is required for cell viability. The results presented here demonstrate that an HMG-like protein has an essential physiological function.


1999 ◽  
Vol 181 (11) ◽  
pp. 3594-3598 ◽  
Author(s):  
S. M. O’Malley ◽  
S. L. Mouton ◽  
D. A. Occhino ◽  
M. T. Deanda ◽  
J. R. Rashidi ◽  
...  

ABSTRACT Vibrio alginolyticus, Vibrio fluvialis, andVibrio parahaemolyticus utilized heme and hemoglobin as iron sources and contained chromosomal DNA similar to severalVibrio cholerae heme iron utilization genes. A V. parahaemolyticus gene that performed the function of V. cholerae hutA was isolated. A portion of the tonB1locus of V. parahaemolyticus was sequenced and found to encode proteins similar in amino acid sequence to V. cholerae HutW, TonB1, and ExbB1. A recombinant plasmid containing the V. cholerae tonB1 and exbB1D1 genes complemented a V. alginolyticus heme utilization mutant. These data suggest that the heme iron utilization systems of the pathogenic vibrios tested, particularly V. parahaemolyticusand V. alginolyticus, are similar at the DNA level, the functional level, and, in the case of V. parahaemolyticus, the amino acid sequence or protein level to that of V. cholerae.


HortScience ◽  
2002 ◽  
Vol 37 (1) ◽  
pp. 187-190 ◽  
Author(s):  
Kentaro Kitahara ◽  
Shogo Matsumoto

An S-allele cDNA was cloned from pistils of 'McIntosh' apple (Malus ×domestica Borkh.). The allele, designated Si in Japan and S10 in Europe, is an S-RNase that is very similar (94%) to the S3-RNase at the deduced amino acid sequence level. This allele can be detected by amplification using the polymerase chain reaction (PCR) and specific primers, followed by digestion with restriction enzyme EheI. The S10 allele was discovered in 'Empire', 'Maypole', 'Shinano Red', 'Spencer', and 'Vista Bella'. The S-allele cDNAs sequenced to date are listed with their Japanese and European designations.


2005 ◽  
Vol 187 (8) ◽  
pp. 2698-2704 ◽  
Author(s):  
Austin L. Hughes ◽  
Robert Friedman

ABSTRACT The pattern of nucleotide substitution was examined at 2,129 orthologous loci among five genomes of Staphylococcus aureus, which included two sister pairs of closely related genomes (MW2/MSSA476 and Mu50/N315) and the more distantly related MRSA252. A total of 108 loci were unusual in lacking any synonymous differences among the five genomes; most of these were short genes encoding proteins highly conserved at the amino acid sequence level (including many ribosomal proteins) or unknown predicted genes. In contrast, 45 genes were identified that showed anomalously high divergence at synonymous sites. The latter genes were evidently introduced by homologous recombination from distantly related genomes, and in many cases, the pattern of nucleotide substitution made it possible to reconstruct the most probable recombination event involved. These recombination events introduced genes encoding proteins that differed in amino acid sequence and thus potentially in function. Several of the proteins are known or likely to be involved in pathogenesis (e.g., staphylocoagulase, exotoxin, Ser-Asp fibrinogen-binding bone sialoprotein-binding protein, fibrinogen and keratin-10 binding surface-anchored protein, fibrinogen-binding protein ClfA, and enterotoxin P). Therefore, the results support the hypothesis that exchange of homologous genes among S. aureus genomes can play a role in the evolution of pathogenesis in this species.


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