Correspondence of Apoproteins of Light-Harvesting Chlorophyll a/b Complexes Associated with Photosystem I to cab Genes: Evidence for a Novel Type IV Apoprotein

Apoproteins of spinach and pea light-harvesting chlorophylla/b complexes associated with photosystem I (LHCI) were identifiedby their chlorophyll fluorescence spectra and protein sequences.Spinach LHCI holocomplex consisted of four apoproteins of 25kDa, 23 kDa, 21 kDa and 20.5 kDa. LHCI subcomplex isolated bysucrose density gradient centrifugation fluoresced at 680 nmwith a shoulder around 700–710 nm at 77 K. It containedthe 23 kDa protein of which the N-terminal sequence correspondedto Type II gene of LHCI. Another LHCI subcomplex isolated bygel electrophoresis emitted at 679 nm and contained the 25 kDaprotein, of which the N-terminus was blocked. Its internal sequenceswere determined after protease treatment and found to be homologousto Type III gene of LHCI. An oligomeric subcomplex of LHCI isolatedby gel electrophoresis emitted at 726 nm and consisted of the21 kDa and 20.5 kDa apoproteins. N-terminal sequence of the20.5 kDa component corresponded to the Type I gene of LHCI.The 21 kDa component did not have any clear homologue, but itsN-terminal sequence was weakly but significantly homologousto all LHC components particularly to Type I LHCI among others.It was, thus, concluded that the 21 kDa protein is the fourthtype of LHCI apoprotein. Similar sequence homology was foundfor pea LHCI apoproteins. (Received September 10, 1990; Accepted November 22, 1990)     

Ligand-sensitive binding of actin-binding protein to immunoglobulin G Fc receptor I (Fc gamma RI).

The high affinity receptor that binds the Fc domain of immunoglobulin G (IgG) subclasses 1 and 3 (Fc gamma RI) mediates important immune defense functions by inducing cell surface changes on human leukocytes. In this article, we document direct high affinity binding of Fc gamma RI to the actin filament cross-linking protein, actin-binding protein (ABP). In the absence of IgG, all Fc gamma RI molecules in undifferentiated cells of myeloid line U937 bound to ABP over a 9-fold range of Fc gamma RI expression induced by human IFN-gamma. Binding of IgG to U937 cells constitutively expressing Fc gamma RI or to COS cells genetically transfected to express Fc gamma RI rapidly decreased the avidity of Fc gamma RI for ABP. This finding suggests the existence of a pathway communicating a signal between a functional IgG receptor and intracellular components involved in the effector responses to Fc gamma RI-ligand interaction.     

Effects of non-MHC loci on resistance to retrovirus-induced immunodeficiency in mice

Mice of certain strains are highly sensitive to development of a severe immunodeficiency disease following inoculation as adults with LP-BM5 murine leukemia viruses (MuLV) whereas others are extremely resistant. These strain-dependent differences in response to infection have been shown to be genetically determined with resistance to disease being, in general, associated with homozygosity for Fv-1 ⁿand H-2 haplotypes a and d and sensitivity with homozygosity for Fv-1 ^band other H-2 haplotypes including b, s, and q. The Fv-1 ^b, H-2 ^rstrain RIIIS/J (RIIIS) was found to be highly resistant to disease even though B10.RIII(71NS)/J (B10.RIII), also H-2 ^r, was very sensitive, thus excluding a role for H-2 in the resistance of RIIIS. The characteristics of RIIIS resistance were evaluated in studies of infected (B10.RIII×RIIIS) F₁, F₂ and reciprocal backcross mice. Resistance to disease was shown to be semidominant and determined by more than one gene, although a preponderant influence of a single gene was suggested. Studies of segregating populations showed that resistance was not associated with or linked to polymorphisms of the V _\complex or genes in proximity to the Emv-2 locus on chromosome 8. However, there was almost complete concordance between absence of disease in infected mice and inhibition of ecotropic virus spread. These results demonstrate that genes other than Fv-1 or H-2 can profoundly influence the development of retrovirus-induced immunodeficiency and replication of ecotropic viruses.Abbreviations MuLV murine leukemia virus - MCF mink cell focus-inducing MuLV - B6 C57BL/6 - BM5d the defective virus in LP-BM5 MuLV - MAIDS murine acquired immunodeficiency syndrome - RIIIS RIIIS/J - B10.RIII B10.RIII (71NS)/J - MLR mixed lymphocyte reaction - FACS fluorescence activated cell sorter     

Immunological detection of the dystrophin molecule with antibody directed against the synthetic peptide.

We synthesized a peptide designated R8 (amino acid residues 1157-1201) based on the primary structure presumed from the nucleotide sequence of the cDNA clone from the gene for Duchenne muscular dystrophy. Antibody to the synthetic R8 generated by immunization of rabbits was tested on human and mouse skeletal muscle by Western blotting analysis. The antibody reacted with a component of the 400K dystrophin of normal human and mouse skeletal muscles, but not with components of the muscles of Duchenne muscular dystrophy patients and mdx mice. Thus we established that this peptide sequence is in fact missing in the protein product 'dystrophin' encoded by the DMD gene. The antibody may prove useful for the diagnosis of the Duchenne types of muscular dystrophy.     

Monoclonal antibodies that depress a specific subset of multiple components of the glutathione-induced response ofHydra

Summary Reduced glutathione evokes a feeding response, the tentacle-ball formation inHydra japonica. This response consists of at least 5 components (R1–R5). We raised 6 monoclonal antibodies (mAbs), each of which depressed a specific subset of these components, and we also examined the immunocytochemical localization of antigens with these mAbs at light microscopic level. The 2 mAbs that depressed R2 and R4 bound to the cnidocils of the desmoneme and the stenotele nematocytes; the 3 mAbs that depressed R5 bound to the apical surface adjacent to the cnidocils of the nematocytes; and the 2 mAbs that depressed R1 and R3 bound to the apical spot structures of unidentified cells in the ectoderm.Together with the specificity of the action of the mAbs on the behavioral response, the correspondence between the effects on the response and the structures visualized with these mAbs suggests that these structures include components of the receptor-effector system relevant to chemoreception.     

Nucleotide sequence of the gene for aqualysin I (a thermophilic alkaline serine protease) of Thermus aquaticus YT-1 and characteristics of the deduced primary structure of the enzyme

Aqualysin I is an alkaline serine protease which is secreted into the culture medium by Thermus aquaticus YT-1, an extreme thermophile [Matsuzawa, H., Hamaoki, M. & Ohta, T. (1983) Agric. Biol. Chem. 47, 25-28]. The gene encoding aqualysin I was cloned into Escherichia coli using synthetic oligodeoxyribonucleotides as hybridization probes. The nucleotide sequence of the cloned DNA was determined. The primary structure of aqualysin I, deduced from the nucleotide sequence, agreed with the NH2-terminal sequence previously reported and the determined amino acid sequences, including the COOH-terminal sequence, of the tryptic peptides derived from aqualysin I. Aqualysin I comprised 281 amino acid residues and its molecular mass was determined to be 28,350. On alignment of the whole amino acid sequence, aqualysin I showed high sequence homology with the subtilisin-type serine proteases, and 43% identity with proteinase K, 37-39% with subtilisins and 34% with thermitase. Extremely high sequence identity was observed in the regions containing the active-site residues, corresponding to Asp32, His64 and Ser221 of subtilisin BPN'. The nucleotide sequence of the cloned DNA (1105 nucleotides) revealed that it contains the entire gene encoding aqualysin I and one open reading frame without a translational stop codon. Therefore, aqualysin I was considered to be produced as a large precursor, which contains a NH2-terminal portion, the protease and a COOH-terminal portion. The G + C content of the coding region for aqualysin I was 64.6%, which is lower than those of other Thermus genes (68-74%). The codon usage in the aqualysin I gene was rather random in comparison with that in other Thermus genes.     

Sequence and over-expression of subunits of adenosine triphosphate synthase in thermophilic bacterium PS3

The primary structures of all the subunits of thermophilic ATP synthase were determined, and its alpha, beta and gamma subunits could be over-expressed in Escherichia coli, because these subunits were stable and reconstitutable. DNA of 7500 base pairs in length was found to contain a cluster of nine genes for subunits of ATP synthase. The order of their reading frames (size in base pairs) was: I(381): a(630): c(216): b(489): delta(537): alpha(1507): gamma(858): beta(1419): epsilon(396), I being a gene for a small hydrophobic, basic protein expressed in vitro. All the termini of TF0F1 subunits were confirmed by peptide sequencing. Large quantities of the overexpressed thermophilic alpha, beta and gamma subunits were prepared from the extract of E. coli, by a few purification steps.     

Rat ovarian and adrenal prolactin receptors. Sizes and effects of divalent metal ions

Receptor fractions were prepared from follicle-rich ovaries (for FSH), luteal cell-rich ovaries (for LH and PRL), and adrenals (for PRL) of rats. Divalent metal ions, Mg++, Ca++, and Mn++ showed inhibitory effects on the binding of LH and FSH to their receptors. The binding of the former was more sensitive to these ions than the latter. On the other hand they showed bell-shaped promotive effects on PRL-ovarian receptor binding, the maximal effects being observed at 10-20 mM. Besides these ions, Ba++ also had a promotive effect, while other divalent metal ions such as Zn++, Cd++, Ni++, and Co++ showed inhibitory effects on PRL-ovarian receptor binding at 5 mM. Mg++ and Ca++ also promoted PRL-adrenal receptor binding, while Mn++ promoted the binding at 10 mM but inhibited it at higher concentrations. Association constant (Ka) and binding capacity (Bmax) of PRL receptors of the ovary and the adrenal were significantly different (ovary: Ka = 0.69 X 10(10) M-1, Bmax = 62 fmol/mg protein, adrenal: Ka = 0.21 X 10(10) M-1, Bmax = 99 fmol/mg protein). Ka of the ovarian PRL receptor was not influenced by these divalent ions, while that of the adrenal receptor was doubled by Ca and Mn ions, Bmax of the latter was also increased. A cooperative effect of Mg and Ca ions was observed on Ka and Bmax of the adrenal receptor. The sizes of the PRL binding sites of these organs revealed by affinity labelling were 17K and 40K in the ovary, and 40K and 110K in the adrenal. These results indicate the different properties of receptors in these different target organs.     

Population Genetics of an Expanding Family of Mobile Genetic Elements

A model of an expanding family of dispersed repetitive DNA was studied. Based on the previous result of the model of duplicative transposition, an approximate solution to give allelism and identify coefficients as functions of time was obtained, and theoretical predictions were verified by Monte Carlo experiments. The results show that, even if the copy number per genome increases very rapidly, allelism and identity coefficients may take a long time to reach equilibrium. The changes of allelism and allelic identity are similar to that of homozygosity at an ordinary single locus, whereas that of nonallelic identity can be much slower, particularly when the copy number per genome is large. Thus, many existing families of highly repetitive sequences may represent nonequilibrium states for nonallelic identity. The present model may be extended to include other evolutionary forces such as gene conversion or the recurrent insertion from normal gene copies.