Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A comparison of the anatomy, fiber type profiles, and contractile properties of the wrist flexor muscles was undertaken in the cat. Isometric contractile characteristics were measured for each muscle. Three muscle fiber types, FG, FOG, and SO, were differentiated by staining cross sections of each muscle for ATPase, NADH diaphorase, SDH, and alpha-GPD activities. The wrist flexor muscles ranged from less than 1% to 49% SO fiber content; with two of the five heads of the flexor digitorium profundus (FDP) having 1% or less SO fibers (FDP1-1.07%, FDP5-0.81%) and the humeral head of the flexor carpi ulnaris muscle (FCUh) having the greatest content of SO fibers. The mean contraction time (CT) plus one-half relaxation time for an isometric twitch was correlated with the percentage of SO fibers and ranged from 40.5 to 111.8 ms. Except for the FCU (37ms), the CT was less than 25 ms for the wrist flexor muscles. The uniarticular wrist flexor muscles, the flexor carpi radialis (FCR), and the FCU had the highest percentage of SO fibers and were more fatigue-resistant that the multiarticular muscles. Considerable differences exist in muscle structure, fiber type proportions, and contractile properties between the FCR and FCU, which may be related to functional differences between the two sides of the wrist that may exist during the placement of the foot during locomotion.
Anat Rec 1981 Mar
PMID:Morphological organization and contractile properties of the wrist flexor muscles in the cat. 725 81

Muscle cell fiber types in gracilis, rectus femoris, and long head of triceps brachii muscles of ferrets and dogs were identified on serial sections stained for myosin ATPase after preincubation at pH values of 9.8, 4.6, and 4.3 and for NADH-tetrazolium reductase (NADH-TR) activity. Although fiber types I and II were identified, the ATPase stain did not demonstrate classic type IIA/IIB fiber differences in either species. However, two type II fiber subtypes could be distinguished in the ferret because they differed slightly in staining intensity with ATPase at pH 4.3 and markedly with NADH-TR. One ferret type II fiber (designated II dark or IID) was smaller, slightly darker on ATPase, more oxidative on NADH-TR, and comprised more muscle volume than the other type II fiber (designated II light IIL). The IID fibers of ferret may represent the IID/X fibers of other authors. Both ferret type II fiber subtypes stained darker at pH 4.3 than canine II fibers. The NADH-TR staining indicated high oxidative activity in canine and ferret type I fibers. In contrast, type II fibers in the dog and IIL fibers in the ferret were moderately oxidative. Canine type IIC fibers were intermediate between type I and type II, whereas in the ferret, type IIC fibers were highly oxidative, as were type IID fibers. Ferret muscles are more oxidative than canine muscles according to NADH-TR staining. Also, ferret muscles possess 40-100% higher citrate synthase activity as compared to canine muscles.
Anat Rec 1993 Aug
PMID:Comparison of muscle cell fiber types and oxidative capacity in gracilis, rectus femoris, and triceps brachii muscles in the ferret (Mustela putorius furo) and the domestic dog (Canis familiaris). 769 Oct 36

Four fiber types have been characterized in different pigeon skeletal muscles according to their innervation pattern (nerve ending structure and innervation distribution) and histochemical properties (SDH and m-ATPase activities). All fast fibers, types IIA and IIB, present aggregated distribution of their nerve endings with "en plaque" structures and very low innervation frequencies. The two kinds of slow fibers recognized are multiple innervated and present higher innervation frequencies. However, type I fibers have nerve terminals in small knobs with uniform localization, whereas type III fibers present "en grappe" nerve endings, which tend to be randomly distributed. Fiber type composition of skeletal muscles has been found closely related to their biomechanical function. Fast fibers are predominant in muscles with an active role in locomotive movements, whereas slow fibers are mainly or exclusively located in postural muscles.
Anat Rec 1993 Oct
PMID:Innervation distribution pattern, nerve ending structure, and fiber types in pigeon skeletal muscle. 823 69

Inactivation of Bacillus subtilis orf1177 in an otherwise Rec+ strain reduced genetic exchange and DNA repair. When the mutation was transferred into a set of recombination-deficient and repair-deficient strains, the DNA repair and recombination ability of the double or triple mutant strains was drastically reduced. B. subtilis Orf1177 protein shares substantial homology with the Escherichia coli Mdf, RecG and UvrB proteins. In vivo analysis of UV-induced mutations suggests that Orf1177 is necessary for strand-specific DNA repair, as is the case for the E. coli MFD protein. Therefore, orf1177 and Orf1177 were termed mfd gene and Mfd protein, respectively. The purified Mfd protein has a native molecular mass of 140 kDa (expected molecular mass 133 kDa). The Mfd protein is a sequence-independent DNA binding protein with weak ATPase activity. The Mfd protein was able to displace in vitro B. subtilis or E. coli RNA polymerase stalled at a lesion. Therefore, Mfd protein appears to target the transcribed strand for repair by recognizing a stalled RNA polymerase and dissociating it from the DNA. In addition, the strong recombination-deficient phenotype of mfd- rec- strains suggest that Mfd protein is involved in homologous DNA recombination.
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PMID:The Mfd protein of Bacillus subtilis 168 is involved in both transcription-coupled DNA repair and DNA recombination. 859 98

The PriA protein, a component of the phiX174-type primosome, was previously shown to be essential for damage-inducible DNA replication in Escherichia coli, termed inducible stable DNA replication. Here, we show that priA::kan null mutants are defective in transductional and conjugational homologous recombination and are hypersensitive to mitomycin C and gamma rays, which cause double-strand breaks. The introduction of a plasmid carrying the priA300 allele, which encodes a mutant PriA protein capable of catalyzing the assembly of an active primosome but which is missing the n'-pas-dependent ATPase, helicase, and translocase activities associated with PriA, alleviates the defects of priA::kan mutants in homologous recombination, double-strand break repair, and inducible stable DNA replication. Furthermore, spa-47, which was isolated as a suppressor of the broth sensitivity of priA::kan mutants, suppresses the Rec- and mitomycin C sensitivity phenotypes of priA::kan mutants. The spa-47 suppressor mutation maps within or very near dnaC. These results suggest that PriA-dependent primosome assembly is crucial for both homologous recombination and double-strand break repair and support the proposal that these processes in E. coli involve extensive DNA replication.
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PMID:The DNA replication priming protein, PriA, is required for homologous recombination and double-strand break repair. 863

First identified as an essential component of the phi X174 in vitro DNA replication system, PriA has ATPase, helicase, translocase, and primosome-assembly activities. priA1::kan strains of Escherichia coli are sensitive to UV irradiation, deficient in homologous recombination following transduction, and filamentous. priA2::kan strains have eightfold higher levels of uninduced SOS expression than wild type. We show that (1) priA1::kan strains have eightfold higher levels of uninduced SOS expression, (2) priA2::kan strains are UVS and Rec-, (3) lexA3 suppresses the high basal levels of SOS expression of a priA2::kan strain, and (4) plasmid-encoded priA300 (K230R), a mutant allele retaining only the primosome-assembly activity of priA+, restores both UVR and Rec+ phenotypes to a priA2::kan strain. Finally, we have isolated 17 independent UVR Rec+ revertants of priA2::kan strains that carry extragenic suppressors. All 17 map in the C-terminal half of the dnaC gene. DnaC loads the DnaB helicase onto DNA as a prelude for primosome assembly and DNA replication. We conclude that priA's primosome-assembly activity is essential for DNA repair and recombination and that the dnaC suppressor mutations allow these processes to occur in the absence of priA.
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PMID:Differential suppression of priA2::kan phenotypes in Escherichia coli K-12 by mutations in priA, lexA, and dnaC. 872 57

Differentiation of odontoblasts involves cell-to-cell recognition, contact stabilization involving the formation of attachment specializations, cytoplasmic polarization, development of the protein synthetic and secretory apparatus, and the active transport of mineral ions. The secretory odontoblast is characterized by an extensive rough-surfaced endoplasmic reticulum, a highly developed Golgi complex, and the presence of specific secretion granules. Type I collagen, a major constituent of dentin matrix, appears to be secreted by the odontoblast into predentin at the proximal portion of the odontoblast process, the major cytoplasmic process extending from the odontoblast cell body into the dentin. The odontoblast process contains a rich network of microtubules and microfilaments. The proximal portion of the process is also a site of fluid-phase endocytosis. Adjacent odontoblasts are held together by numerous macula adherens junctions and a well-developed distal junctional complex adjacent to be predentin. Junctional strands of the occludens type have been observed to be a component of this junctional complex. Tracer studies employing horseradish peroxidase indicate that this junctional complex does not form a tight barrier to the diffusion of tissue fluid from the interodontoblast spaces into the predentin. Many well-developed gap junctions are formed between adjacent odontoblasts and between odontoblasts and the fibroblasts that make up the subodontoblastic layer. Ca-ATPase activity is demonstrated in the Golgi complex and mitochondrial cristae and along the distal plasma membranes of odontoblasts. ALPase activity is also intense along the entire odontoblast cell surface. The osmium tetroxide-pyroantimonate technique for calcium localization demonstrates prominent reaction precipitates in mitochondria of odontoblasts. Energy-dispersive x-ray microanalysis of anhydrously fixed and processed odontoblasts detected Ca and P peaks throughout the cytoplasm. A sulfur peak is noted in the distal cytoplasm of odontoblasts and in matrix vesicles. Together, these results demonstrate the complexity and variety of cell functions involved in dentinogenesis.
Anat Rec 1996 Jun
PMID:Structure and organization of odontoblasts. 876 66

The Pk-rec gene, encoding a RecA/RAD51 homologue from the hyperthermophilic archaeon Pyrococcussp. KOD1, was expressed in Escherichia coli. The recombinant Pk-REC was purified to homogeneity and was shown to be in a dimeric form. A striking property of the purified recombinant Pk-REC was the unusual DNase activity on both single- and double-stranded DNAs along with the ATPase activity. The reaction product of this DNase activity was mononucleotides. The optimum temperature and pH for the DNase activity were 60 degrees C and 8-8.5, respectively. In addition, the metal ion requirement for DNase activity was different from that for the ATPase activity. The protein exhibited no DNase activity in the presence of Zn2+ion, which was one of the most preferable divalent cations for ATPase activity. Another unique characteristic of the recombinant protein was that the reaction product of ATPase activity was AMP instead of ADP.Pk-REC may represent a common prototype of the RecA family proteins with high RecA-like activity.
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PMID:Characterization of a RecA/RAD51 homologue from the hyperthermophilic archaeon Pyrococcus sp. KOD1. 901 20

The RAD51 gene is a eukaryotic homolog of rec A, a critical component in homologous recombination and DNA repair pathways in Escherichia coli . We have cloned the RAD51 homolog from Tetrahymena thermophila , a ciliated protozoan. Tetrahymena thermophila RAD51 encodes a 36.3 kDa protein whose amino acid sequence is highly similar to representative Rad51 homologs from other eukaryotic taxa. Recombinant Rad51 protein was purified to near homogeneity following overproduction in a bacterial expression system. The purified protein binds to both single- and double-stranded DNA, possesses a DNA-dependent ATPase activity and promotes intermolecular ligation of linearized plasmid DNA. While steady-state levels of Rad51 mRNA are low in normally growing cells, treatment with UV light resulted in a >100-fold increase in mRNA levels. This increase in mRNA was time dependent, but relatively independent of UV dose over a range of 1400-5200 J/m2. Western blot analysis confirmed that Rad51 protein levels increase upon UV irradiation. Exposure to the alkylating agent methyl methane sulfonate also resulted in substantially elevated Rad51 protein levels in treated cells, with pronounced localization in the macronucleus. These data are consistent with the hypothesis that ciliates such as T.thermophila utilize a Rad51-dependent pathway to repair damaged DNA.
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PMID:Identification and characterization of the RAD51 gene from the ciliate Tetrahymena thermophila. 962 14

A RecA/Rad51 homologue from Pyrococcus kodakaraensis KOD1 (Pk-REC) is the smallest protein among various RecA/Rad51 homologues. Nevertheless, Pk-Rec is a super multifunctional protein and shows a deoxyribonuclease activity. This deoxyribonuclease activity was inhibited by 3 mM or more ATP, suggesting that the catalytic centers of the ATPase and deoxyribonuclease activities are overlapped. To examine whether these two enzymatic activities share the same active site, a number of site-directed mutations were introduced into Pk-REC and the ATPase and deoxyribonuclease activities of the mutant proteins were determined. The mutant enzyme in which double mutations Lys-33 to Ala and Thr-34 to Ala were introduced, fully lost both of these activities, indicating that Lys-33 and/or Thr-34 are important for both ATPase and deoxyribonuclease activities. The mutation of Asp-112 to Ala slightly and almost equally reduced both ATPase and deoxyribonuclease activities. In addition, the mutation of Glu-54 to Gln did not seriously affect the ATPase, deoxyribonuclease, and UV tolerant activities. These results strongly suggest that the active sites of the ATPase and deoxyribonuclease activities of Pk-REC are common. It is noted that unlike Glu-96 in Escherichia coli RecA, which has been proposed to be a catalytic residue for the ATPase activity, the corresponding residual Glu-54 in Pk-REC is not involved in the catalytic function of the protein.
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PMID:A unique DNase activity shares the active site with ATPase activity of the RecA/Rad51 homologue (Pk-REC) from a hyperthermophilic archaeon. 1006 83


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