Search results for "Multigene family"
showing 10 items of 134 documents
Molecular Evolution of the Globin Gene Cluster E in Two Distantly Related Midges, Chironomus pallidivittatus and C. thummi thummi
1998
We have studied the evolutionary dynamics of a cluster of insect globin genes by comparing the organization and sequence of the gene group in two distantly related species, Chironomus pallidivittatus and C. t. thummi. Although the general architecture of the globin gene cluster has been conserved, we have found an additional, previously undescribed gene (named Cpa F) in C. pallidivittatus which shows signs of accelerated sequence evolution at nonsynonymous codon positions. This new gene is clearly functional, as demonstrated by Northern analysis. Comparison of paralogous and orthologous genes reveals patterns of intraspecific sequence homogenization. The head-to-head-oriented globin 3 and 4…
Copy-number fluctuation by unequal crossing-over in the chicken avidin gene family.
2001
The chicken avidin gene (AVD) forms a closely clustered gene family together with several avidin-related genes (AVRs). In this study, we used fluorescence in situ hybridization on extended DNA fibers (fiber-FISH) to show that the number of the AVD and AVR genes differs between individuals. Furthermore, the gene copy-number showed wide somatic variation in white blood cells of the individuals. The molecular mechanism underlying the fluctuation is most probably unequal crossing-over and/or unequal sister chromatid exchange, as judged by the Gaussian distribution of the gene counts. By definition, an increase in gene number on one locus should be accompanied by a decrease on the other locus in…
Specific and promiscuous functions of multiple DnaJ proteins in Synechocystis sp. PCC 6803
2011
Cyanobacterial genomes typically encode multiple Hsp70 (DnaK) and Hsp40 (DnaJ) chaperones, and in the genome of the cyanobacteriumSynechocystisPCC 6803, three DnaK proteins are encoded together with seven DnaJ proteins. While only two of the DnaJ proteins can complement the growth defect of anEscherichia coliΔdnaJstrain, only disruption of thednaJgenesll0897resulted in a growth defect at elevated temperatures. Based on the domain structure and the phenotype observed following disruption of the encoding gene, Sll0897 can be classified as a canonical heat-shock protein inSynechocystis. Furthermore, mostdnaJgenes could be deleted individually, whereas disruption of the gene encoding the DnaJ S…
7E olfactory receptor gene clusters and evolutionary chromosome rearrangements
2005
Olfactory receptor (OR) genes of the 7E subfamily have been duplicated to multiple regions throughout the human genome. Segmental duplications containing 7E OR genes have been associated with both pathological and evolutionary chromosome rearrangements. Many of these breakpoint regions coincide with breaks of chromosomal synteny in the mouse, rat and/or chicken genomes. Collectively, these data suggest that 7E OR-containing regions represent hot spots of genomic instability.
Genetics of Inflammation in Age-Related Atherosclerosis: Its Relevance to Pharmacogenomics
2007
In response to tissue injury elicited by trauma or infection, the inflammatory response, as a complex network of molecular and cellular interactions, sets an answer directed to facilitate a return to physiological homeostasis and tissue repair. The role of the genetic background and the subsequent predisposition toward the extent of the inflammatory response is determined by gene variability encoding endogenous mediators involved in the inflammatory pathway. Due to its clinical relevance, the genetics of inflammation in aging will be studied using an inflammatory disease like atherosclerosis as an example. Several studies have reported a significant difference in distribution, between patie…
Rat mammary-gland transferrin: nucleotide sequence, phylogenetic analysis and glycan structure
1995
The complete cDNA for rat mammary-gland transferrin (Tf) has been sequenced and also the native protein isolated from milk in order to analyse the structure of the main glycan variants present. A lactating-rat mammary-gland cDNA library in lambda gt10 was screened with a partial cDNA copy of rat liver Tf and subsequently rescreened with 5′ fragments of the longest clones. This produced a 2275 bp insert coding for an open reading frame of 695 amino acid residues. This includes a 19-amino acid signal sequence and the mature protein containing 676 amino acids and one N-glycosylation site in the C-terminal domain at residue 490. Phylogenetic analysis was carried out using 14 translated Tf nucle…
Identification of a positively evolving putative binding region with increased variability in posttranslational motifs in zonadhesin MAM domain 2.
2005
Positive selection has been shown to be pervasive in sex-related proteins of many metazoan taxa. However, we are only beginning to understand molecular evolutionary processes on the lineage to humans. To elucidate the evolution of proteins involved in human reproduction, we studied the sequence evolution of MAM domains of the sperm-ligand zonadhesin in respect to single amino acid sites, solvent accessibility, and posttranslational modification. GenBank-data were supplemented by new cDNA-sequences of a representative non-human primate panel. Solvent accessibility predictions identified a probably exposed fragment of 30 amino acids belonging to MAM domain 2 (i.e., MAM domain 3 in mouse). The…
Membrane-insertion fragments of Bcl-xL, Bax, and Bid.
2004
Apoptosis regulators of the Bcl-2 family associate with intracellular membranes from mitochondria and the endoplasmic reticulum, where they perform their function. The activity of these proteins is related to the release of apoptogenic factors, sequestered in the mitochondria, to the cytoplasm, probably through the formation of ion and/or protein transport channels. Most of these proteins contain a C-terminal putative transmembrane (TM) fragment and a pair of hydrophobic alpha helices (alpha5-alpha6) similar to the membrane insertion fragments of the ion-channel domain of diphtheria toxin and colicins. Here, we report on the membrane-insertion properties of different segments from antiapopt…
Artificial Chromosomes to Explore and to Exploit Biosynthetic Capabilities of Actinomycetes
2012
Actinomycetes are an important source of biologically active compounds, like antibiotics, antitumor agents, and immunosuppressors. Genome sequencing is revealing that this class of microorganisms has larger genomes relative to other bacteria and uses a considerable fraction of its coding capacity (5–10%) for the production of mostly cryptic secondary metabolites. To access actinomycetes biosynthetic capabilities or to improve the pharmacokinetic properties and production yields of these chemically complex compounds, genetic manipulation of the producer strains can be performed. Heterologous expression in amenable hosts can be useful to exploit and to explore the genetic potential of actinom…
Evolutionary history of the OmpR/IIIA family of signal transduction two component systems in Lactobacillaceae and Leuconostocaceae
2011
15 pages, 3 tables, 7 figures.