A comparison of GABAC and ρ subunit receptors from the white perch retina

1997 ◽  
Vol 14 (5) ◽  
pp. 843-851 ◽  
Author(s):  
Aohua Qian ◽  
George Hyatt ◽  
Andres Schanzer ◽  
Rohan Hazra ◽  
Abigail S. Hackam ◽  
...  

AbstractThere is increasing evidence that GABAC receptors are composed of GABA ρ subunits. In this study, we compared the properties of native GABAC receptors with those of receptors composed of a GABA ρ subunit. A homologue of the GABA ρ gene was cloned from a white perch (Roccus americana) retinal cDNA library. The clone (perch-s) has an open reading frame of 1422 nucleotide base pairs and encodes a predicted protein of 473 amino acids. It is highly homologous to GABA ρ subunits cloned from human and rat retinas. The receptors (perch-s receptor) expressed by this gene in Xenopus oocytes show properties similar to those of the GABAC receptors present on white perch retinal neurons. GABA induced a sustained response that had a reversal potential of –27.1 +minus; 3.6 mV. The EC50 for the response was 1.74 +− 1.25 μM, a value similar to that reported for GABAC receptors. Pharmacologically, the responses were bicuculline insensitive and not modulated by either diazepam or pentobarbital as is the case for GABAc receptors. There were, however, some distinct differences between native GABAc and perch-s receptors. I4AA acts as a partial agonist on perch-s receptors whereas it is strictly an antagonist on native GABAC receptors. Picrotoxin inhibition is noncompetitive on perch-s receptors, but both competitive and noncompetitive on GABAC receptors. We conclude that GABAC receptors are formed by GABA p subunits but that native GABAc receptors probably consist of a mixture of GABA ρ subunits.

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 644-651 ◽  
Author(s):  
Kenneth Koo ◽  
W. Dorsey Stuart

The gene product of the mtr locus of Neurospora crassa is required for the transport of neutral aliphatic and aromatic amino acids via the N system. We have previously cloned three cosmids containing Neurospora DNA that complement the mtr-6(r) mutant allele. The cloned DNAs were tightly linked to restriction fragment length polymorphisms that flank the mtr locus. A 2.9-kbp fragment from one cosmid was subcloned and found to complement the mtr-6(r) allele. Here we report the sequence of the fragment that hybridized to a poly(A)+ mRNA transcript of about 2300 nucleotides. We have identified an 845-bp open reading frame (ORF) having a 59-bp intron as the potential mtr ORF. S1 nuclease analysis of the transcript confirmed the transcript size and the presence of the intron. A second open reading frame was found upstream in the same reading frame as the mtr ORF and appears to be present in the mRNA transcript. The mtr ORF is predicted to encode a 261 amino acid polypeptide with a molecular mass of 28 613 Da. The proposed polypeptide exhibits six potential α-helical transmembrane domains with an average length of 23 amino acids, does not have a signal sequence, and contains amino acid sequence homologous to an RNA binding motif.Key words: sequence, membranes, ribonucleoprotein.


1988 ◽  
Vol 8 (9) ◽  
pp. 3898-3905 ◽  
Author(s):  
C Huxley ◽  
T Williams ◽  
M Fried

The mouse surfeit locus is unusual in that it contains a number of closely clustered genes (Surf-1, -2, and -4) that alternate in their direction of transcription (T. Williams, J. Yon, C. Huxley, and M. Fried, Proc. Natl. Acad. Sci. USA 85:3527-3530, 1988). The heterogeneous 5' ends of Surf-1 and Surf-2 are separated by 15 to 73 base pairs (bp), and the 3' ends of Surf-2 and Surf-4 overlap by 133 bp (T. Williams and M. Fried, Mol. Cell. Biol. 6:4558-4569, 1986; T. Williams and M. Fried, Nature (London) 322:275-279, 1986). A fourth gene in this locus, Surf-3, which is a member of a multigene family, has been identified. The poly(A) addition site of Surf-3 lies only 70 bp from the poly(A) addition site of Surf-1. Transcription of Surf-3 has been studied in the absence of the other members of its multigene family after transfection of a cloned genomic mouse DNA fragment, containing the Surf-3 gene, into heterologous monkey cells. Surf-3 specifies a highly expressed 1.0-kilobase mRNA that contains a long open reading frame of 266 amino acids, which would encode a highly basic polypeptide (23% Arg plus Lys). The other members of the Surf-3 multigene family are predominantly, if not entirely, intronless pseudogenes with the hallmarks of being generated by reverse transcription. The role of the very tight clustering on regulation of expression of the genes in the surfeit locus is discussed.


1986 ◽  
Vol 6 (5) ◽  
pp. 1711-1721
Author(s):  
E M McIntosh ◽  
R H Haynes

The dCMP deaminase gene (DCD1) of Saccharomyces cerevisiae has been isolated by screening a Sau3A clone bank for complementation of the dUMP auxotrophy exhibited by dcd1 dmp1 haploids. Plasmid pDC3, containing a 7-kilobase (kb) Sau3A insert, restores dCMP deaminase activity to dcd1 mutants and leads to an average 17.5-fold overproduction of the enzyme in wild-type cells. The complementing activity of the plasmid was localized to a 4.2-kb PvuII restriction fragment within the Sau3A insert. Subcloning experiments demonstrated that a single HindIII restriction site within this fragment lies within the DCD1 gene. Subsequent DNA sequence analysis revealed a 936-nucleotide open reading frame encompassing this HindIII site. Disruption of the open reading frame by integrative transformation led to a loss of enzyme activity and confirmed that this region constitutes the dCMP deaminase gene. Northern analysis indicated that the DCD1 mRNA is a 1.15-kb poly(A)+ transcript. The 5' end of the transcript was mapped by primer extension and appears to exhibit heterogeneous termini. Comparison of the amino acid sequence of the T2 bacteriophage dCMP deaminase with that deduced for the yeast enzyme revealed a limited degree of homology which extends over the entire length of the phage polypeptide (188 amino acids) but is confined to the carboxy-terminal half of the yeast protein (312 amino acids). A potential dTTP-binding site in the yeast and phage enzymes was identified by comparison of homologous regions with the amino acid sequences of a variety of other dTTP-binding enzymes. Despite the role of dCMP deaminase in dTTP biosynthesis, Northern analysis revealed that the DCD1 gene is not subject to the same cell cycle-dependent pattern of transcription recently found for the yeast thymidylate synthetase gene (TMP1).


2000 ◽  
Vol 66 (12) ◽  
pp. 5480-5483 ◽  
Author(s):  
Sean S. Dineen ◽  
Marite Bradshaw ◽  
Eric A. Johnson

ABSTRACT Boticin B is a heat-stable bacteriocin produced byClostridium botulinum strain 213B that has inhibitory activity against various strains of C. botulinum and related clostridia. The gene encoding the bacteriocin was localized to a 3.0-kb HindIII fragment of an 18.8-kb plasmid, cloned, and sequenced. DNA sequencing revealed the boticin B structural gene,btcB, to be an open reading frame encoding 50 amino acids. A C. botulinum strain 62A transconjugant containing theHindIII fragment inserted into a clostridial shuttle vector expressed boticin B, although at much lower levels than those observed in C. botulinum 213B. To our knowledge, this is the first demonstration and characterization of a bacteriocin from toxigenic group I C. botulinum.


Author(s):  
Sirui Yan ◽  
Yulin Wan ◽  
Ying Zhang ◽  
Shanshan An ◽  
Kaiqiao Yang ◽  
...  

The current pneumonia epidemic in China could evolve into a pandemic on a global scale if not effectively contained. The 2019-nCoV possesses a 61-amino acid open reading frame resembling SARS-CoV virulence factor - ORF6 peptide. The isoleucine content is 15.9% in ORF6 of SARS-CoV versus 16.4% of that in 2019-nCoV. Given the proton affinity in the carbonyl oxygen in isoleucine, augmented proton traffic can enhance proton-ion antiport and prompt cell swelling. As the content of essential amino acids in the open reading frame of 2019-nCoV reaches 57.4%, a starch/vitamin diet served for short period of time does not give rise to essential amino acids and halts virion production, which could be adopted as prophylactic approach of many viral infections. Plant-based diet or fasting/boiled rice water can also minimize the intake of essential amino acids or all amino acids respectively. Calorie restriction has been confirmed in animal studies to extend lifespan, and its underlying mechanism is not fully known. Furthermore, several proteins of 2019-nCoV possess high valine plus glycine content, which is implicated in heart disease.


Development ◽  
1991 ◽  
Vol 113 (4) ◽  
pp. 1435-1449 ◽  
Author(s):  
C. Walther ◽  
P. Gruss

A multigene family of paired-box-containing genes (Pax genes) has been identified in the mouse. In this report, we describe the expression pattern of Pax-6 during embryogenesis and the isolation of cDNA clones spanning the entire coding region. The Pax-6 protein consists of 422 amino acids as deduced from the longest open reading frame and contains, in addition to the paired domain, a paired-type homeodomain. Beginning with day 8 of gestation, Pax-6 is expressed in discrete regions of the forebrain and the hindbrain. In the neural tube, expression is mainly confined to mitotic active cells in the ventral ventricular zone along the entire anteroposterior axis starting at day 8.5 of development. Pax-6 is also expressed in the developing eye, the pituitary and the nasal epithelium.


1999 ◽  
Vol 73 (11) ◽  
pp. 9604-9608 ◽  
Author(s):  
Tsutomu Nishizawa ◽  
Hiroaki Okamoto ◽  
Fumio Tsuda ◽  
Tatsuya Aikawa ◽  
Yoshiki Sugai ◽  
...  

ABSTRACT Three hypervariable regions were identified in a central portion of open reading frame 1 of TT virus DNA, which codes for a putative capsid protein of 770 amino acids. TT virus circulates as quasispecies, with many amino acid substitutions in hypervariable regions, to evade immune surveillance of the hosts and to establish a persistent infection.


2019 ◽  
Vol 8 (33) ◽  
Author(s):  
T. O. C. Faleye ◽  
O. M. Adewumi ◽  
J. A. Adeniji

Here, we describe the genome of an echovirus 7 (E7) isolate of Southeast Asian ancestry recovered from a child in Nigeria with acute flaccid paralysis (AFP). The genome has 7,295 nucleotides (nt) and an open reading frame (ORF) with 2,195 amino acids.


Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S61-S61 ◽  
Author(s):  
Kazu Haino-Fukushima ◽  
Xuxi Fan ◽  
Shouka Nakamura

The vitelline coat (VC) lysin of Tegula, a marine molluscan genus, is released from the acrosome of sperm during fertilisation and can lyse the VC of only the same species. The lytic action of this lysin against the VC is not an enzymatic reaction, but a stoichiometric and irreversible one (Haino-Fukushima, 1974).The VC of Tegula pfeifferi consists of glycoproteins containing sulphated polysaccharides, which account for roughly two-thirds of the entire weight of the VC. The presence of a large quantity of polysaccharides in the VC had prevented rapid progress in the analysis of its protein components. Last year, we succeeded in a complete solubilisation of the VC by boiling for a long time in 1% SDS solution, and determined the cDNA sequence coding for a mature 41 kDa glycoprotein, which appears to be the major component of the VC from the results of SDS-polyacrylamide gel electrophoresis (PAGE). The cDNA, referred to as vcp41, comprises 1072 base pairs and contains one open reading frame with a sequence for 319 amino acids containing 19 amino acids of a signal peptide. The deduced amino acid sequence has five N-glycosylation sites and ten cysteine residues. It seems that almost 7 kDa in this 41kDa glycoprotein is polysaccharide constituents (Fan & Haino-Fukushima, 1998).


1995 ◽  
Vol 22 (3) ◽  
pp. 471 ◽  
Author(s):  
CL Mcintyre ◽  
AL Rae ◽  
MD Curtis ◽  
JM Manners

The isolation and characterisation of a cDNA encoding a caffeic acid 0-methyl transferase cDNA homologue (COMT) from Stylosanthes humilis are described. The clone is 1391 nucleotides in length, with an open reading frame encoding a predicted protein of 366 amino acids. Cluster analysis of the deduced amino acid sequence revealed extensive homology to other published O-methyl transferase sequences. Maximum levels of homology were seen with COMTs from alfalfa (87%) and aspen (84%). Southern analysis suggested that this enzyme is encoded by two genes in S. humilis. The mRNA is most strongly expressed in stem tissue, with intermediate levels of expression in young leaves and roots, and does not appear to be induced upon fungal infection or wounding.


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