Genetic control of two independently segregating loci in mice to the sequential polypeptide (Tyr-Ala-Glu-Gly)n

Immune responses to the sequential helical polypeptide (Tyr-Ala-Glu-Gly)_n [(T-A-G-Gly)_n] in mice is under the control of at least two separate genes. One gene,Ir-(T-A-G-Gly)-1, which is linked, toH-2 haplotypesb, f, andr, controls the ability to respond and maps to theIA subregion. A non-H-2-linked locus,Ir-(T-A-G-Gly)-2. is responsible for the magnitude of the antibody response, which is expressed as a high, intermediate, or low level of antibody production. The antibody produced is of the IgG class, and does not crossreact even with the closely related sequential helical polymer (Tyr-Glu-Ala-Gly)_n [(T-G-A-Gly)_n]. Immune responsiveness is a dominant trait,i.e., the F₁ generations of responder x nonresponder crosses are responders. However, the data obtained with both backcross populations are not easily interpretable. The contribution of the B-cell mitogenic activity of the sequential polymer to activation of suppressor T cells is considered as a possible explanation for the backcross results. The possible role of the Ia. W29 specificity present in the mouse strains responding to both (T-A-G-Gly)_n and calf skin collagen type I in modulating responses to the polymers is discussed.     

Genetic control of acquired resistance to visceral Leishmaniasis in mice

A series ofH-2 and non-H-2 congenic resistant (CR) strains on a C57BL/10Sn background were infected with 10⁷ amastigotes ofLeishmania donovani. Non-H-2 congenic strains B10.LP-H-3 ^b and B10.CE(30NX) and (B10.LP-H-3 ^b × B10)F₁ hybrids showed a very rapid decrease in liver-parasite burdens beyond day 21. Parasite counts for these strains at day 35 were significantly lower than for all other strains tested. The rapid decrease in parasite numbers, massive lymphocellular infiltration into the liver and strong delayed hypersensitivity reactions to parasite antigens in strains congenic for a portion of chromosome 2 indicated that acquired immunity toL. donovani was controlled by a dominant gene at or near theIr-2 locus. In addition, B10.129(10M) mice, which differ from C57BL/10Sn at theH-11 locus, showed highly significant increases in parasite numbers at day 35. Other observations supporting the absence of acquired immunity in B10.129(10M) included negative delayed hypersensitivity tests to parasite antigens and the absence of lymphocellular infiltrate into the liver. Although the differences were not as pronounced,H-2 CR strains withH-2 ^b ,H-2 ^a , andH-2 ^k haplotypes also showed significantly greater decreases in parasite numbers by day 35 as compared to otherH-2 CR strains.     

Polygenic control of the immune response to F antigen

The ability to produce an autoimmune response to F antigen in mice is underH-2-linked and non-H- 2-linkedIr-gene control. There is an absolute requirement for ak allele atH-2K orI-A in order to produce anti-F antibodies. Low and high responsiveness is controlled by a non-H-2-linkedIr gene which behaves in a similar fashion toIr-3, in that as the dose of F-antigen is lowered, low responders behave as high responders and vice versa. This conversion from low to high responsiveness also occurs within a month after ATX.— Most F₁ hybrids derived from (responder x nonresponder) parents bearing identical F-types behave as dominant nonresponders. As a result of ATX, such F₁ mice convert to high responders. This conversion occurs if the animals are not immunized before day 90. If they receive F antigen prior to that time, they remain nonresponders for 7–9 months. One F₁ combination — AKD2 — behaves as a dominant high responder. Genetic analysis showed that in the presence of ak allele atH-2K orI-A, a non-H-2-linkedIr gene inherited from the AKR mice determined dominant responsivenss. No manipulation of the immune response or combination of genes converted nonresponders lacking ak allele into responders. Such complex genetic control suggests regulation by a number of independently segregating loci whose function it is to limit the autoimmune response to F antigen.     

Genetic control of IgM responses to (T,G)-A — L

The primary antibody response to aqueous immunization with a low molecular-weight lot of (T,G)-A — L (#420) was studied in congenic pairs of inbred mouse strains. Two new genetic controls were identified, both of which quantitatively regulate the production of IgM anti-(T,G)-A — L antibody. Testing of F₁ and F₂ progeny demonstrated that one of these genes is linked to the major histocompatibility (H-2) complex, and that high response is dominant over low response. Whether this gene is identical toIr-1A is not yet known. The other gene, designatedIg-TGAL _M , is linked to the immunoglobulin heavy-chain allotype locus (Ig-1) and is expressed in a genedose dependent manner. Following secondary challenge with (T,G)-A — L 420, quantitative differences in IgG antibody response were observed inIr-1A high-responder congenics differing only at theIg-1 locus. Breeding studies, however, failed to demonstrate any linkage between this locus and the quantitative control of IgG anti-(T,G)-A — L antibody. These data demonstrate thatH-2-linked immune response genes can regulate IgM as well as IgG antibody responses, that genetic control of the IgM response to (T,G)-A — L is linked toIg-1, and that bothH-2-linked andIg-1-linked genes may simultaneously affect an IgM antibody response to the same antigen.Abbreviations used in this paper are (T,G)-A — L poly-l-(Tyr,Glu)-poly-d,l-Ala-poly-l-Lys - NMS normal mouse serum - SRBC sheep red blood cells - i.p. intraperitoneal - PBS phosphate-buffered saline - RAMG polyvalent rabbit anti-mouse globulin - 2-Me 2-Mercaptoethanol - 2-MeS 2-Me-sensitive - PFC plaque-forming cells - ABC antigen-binding cells     

Genetic analysis of the non-H-2-linked Ir genes controlling the cytotoxic T-cell response to H-Y in H-2 d mice

The T-cell mediated immune responses to the male specific minor histocompatibility antigen H-Y in mice have been studied extensively as a model for immune responses to other weak antigens like tumor antigens or autoantigens. In a recent analysis of the strain distribution of the cytotoxic T-cell (Tc-cell) responsiveness to H-Y, it has been found that genes both within and outside the H-2 complex exert an interactive control. Whereas the H-2 ^b strains all are high responders, independent of their non-H-2 background, other H-2 haplotypes (d, k, and s) only allow for a response if they are combined with certain non-H-2 genes. The H-2-linked immune response genes (Ir-genes) have been previously mapped to the I and K or D region of the H-2 complex, but the mapping of the non-H-2 genes has not yet been established. In this study evidence is presented, using recombinant inbred strains and immunoglobulin heavy chain (Igh) congenic strains of mice, to show that there is more than one non-H-2 Ir-gene involved, that the main controlling genes are not linked to the Igh complex, and that at least one non-H-2 Ir-gene is linked to the H-3 region on chromosome 2. This region includes genes for beta-2-microglobulin (2m), the Ly-mllalloantigen a polymorphic cell surface glycoprotein (Pgp-1), a B-cell specific antigen Ly-4, a transplantation antigen H-3, and genes (Ir-2) controlling the immune response to Ea-1 and H-13.     

Molecular evidence for the phylogenetic position ofHanabusaya asiatica Nakai (Campanulaceae), an endemic species in Korea

The phylogenetic relationship of the Korean endemic genus,Hanabusaya, to other campanulaceous genera has been controversial since it was described by Nakai in 1911. Three genera of Campanuloideae,Symphyandra, Adenophora, andCampanula, have been considered closely related by various taxonomists on the basis of anther shape, gross morphology, and pollen characters, respectively. We have tested these competing taxonomic hypotheses using the internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA from 12 taxa representing 7 genera of Campanulaceae. The molecular phylogeny indicates strongly thatHanabusaya is more closely allied toAdenophora than toCampanula orSymphyandra. The phylogenetic affinity ofHanabusaya andAdenophora is supported by a 100% bootstrap value and a high decay index (13). The average sequence divergence value (Kimura’s 2-parameter method) betweenHanabusaya and theAdenophora species is 2.58. The value is significantly (about ten times) lower than the ones observed betweenHanabusaya and the species ofCampanula (average of 23.52) and betweenHanabusaya andSymphyandra (24.95). The ITS sequence phylogeny suggests that some morphological characters, such as fused anthers and corolla shape, are homoplastic in the Campanulaceae genera.     

The Mouse Glutathione PeroxidaseGpx2Gene Maps to Chromosome 12; Its PseudogeneGpx2-psMaps to Chromosome 7

TheGPX2gene codes for GSHPx-GI, a glutathione peroxidase whose mRNA is readily detectable in the gastrointestinal tract. AlthoughGPX2is a single gene in humans, there are two genes in the mouse genome with homology toGPX2.By analyzing a panel of mouse interspecies DNA from the Jackson Laboratory's backcross resource, we have chromosomally mapped these two genes. One was mapped to the central region of mouse chromosome 12 betweenD12Mit4andD12Mit5,nearfosandTgfb3.This region is homologous to human 14q24.1, where humanGPX2has been mapped, and most likely represents the functional mouseGpx2gene. The otherGpx2-like gene was mapped to mouse chromosome 7 betweenPcsk3andHbb.We have isolated the latter gene from a P1 phage library. Its pseudogene nature is revealed by the sequence analysis: (a) it is intronless; (b) it has a single nucleotide deletion in the coding region; and (c) it has a poly(A) tail at its 3′-untranslated region.     

Molecular organization of theD-Qa region oft-haplotypes suggests that recombination is an important mechanism for generating genetic diversity of the major histocompatibility complex

We have determined the molecular maps of theH-2D andQa regions of thet-complex haplotypest ^l2 andt ^w5 by chromosomal walking. Analysis with class I probes and other probes unique to theH-2D:Qa subregion indicates that the class I gene organization oft ¹² is:D1-D2-Q1-Q2-Q3-Qx-Q4-Q5-Q10, while that oft ^w5 is:D1-D2-Q1-Q2-Q4-Q5-Q10. Thus, the absence of theQ6-Q9 genes suggested previously int-haplotypes was confirmed. A comparison of the molecular maps of thet ¹² andt ^w5 chromosomes revealed an extremely mosaic pattern of diversity: The regions betweenD1 andD2, and betweenQ4 andQ10, are very similar in both chromosomes. However, theirQ1 toQ3 regions are strikingly different. Further comparisons of wild-type chromosomes and additionalt-haplotypes by molecular mapping and genomic Southern blot hybridization with probes to theQ1-Q3 region showed a high level of polymorphism among both wild-type chromosomes and amongt-haplotypes. The characteristics of the polymorphisms suggest that recombination may play an important role in generating this genetic diversity. Furthermore, recombination between wild-type andt-haplotype chromosomes may be involved.     

A molecular systematic study ofCathaya, a relic genus of thePinaceae in China

The systematic position ofCathaya, a relic genus of thePinaceae, was discussed based on therbcL gene sequence. The sequence data were analysed with PAUP and MEGA programs. The great genetic distance value betweenCathaya and any other genus of thePinaceae showed thatCathaya was a distinct and isolated genus. The most parsimonious Fitch tree and neighbor-joining tree showed thatCathaya was distantly related to the clade comprisingAbies, Keteleeria, Pseudolarix andTsuga, and a sister group relationship betweenCathaya andPinus was weakly supported.Pseudotsuga is closely related toLarix. In theAbies-Keteleeria-Pseudolarix-Tsuga clade,Abies has a close relationship toKeteleeria whilePseudolarix is relatively closely related toTsuga.     

Chloroplast DNA typing by PCR-SSCP in thePinus pumila-P. parviflora var.pentaphylla complex (Pinaceae)

Pinus hakkodensis has been considered as a hybrid betweenP. pumila andP. parviflora var.pentaphylla. Chloroplast DNA typing of this putative hybrid and hypothesized parental species in the Tanigawa Mountains, Japan, was conducted by PCR and single-strand conformation polymorphism (SSCP) of the intergenic spacer betweentrnL(UAA)3′ exon andtrnF(GAA) of cpDNA. Each of the hypothesized parental species collected from other mountain regions displayed a diagnostic SSCP pattern, whereas all morphological intermediates sampled in the Tanigawa Mountains had the SSCP pattern ofP. parviflora var.pentaphylla. Furthermore, some individuals classified on the basis of needle morphology as belonging toP. pumila in this mountain region showed the SSCP pattern ofP. parviflora var.pentaphylla. This may suggest that pollen-mediated uni-directional introgression fromP. parviflora var.pentaphylla toP. pumila occurs in the Tanigawa Mountains.     

Complementation between a gene of theI-E subregion and a non-H-2 gene in the class-specific suppression of IgG2a antibody to sheep erythrocytes

A low level of IgG2a antibodies is observed in B10 mice after primary immunization with SRBC. Analysis of the response in different H-2^b mice and among B10 animals with differentH-2 haplotypes reveals that this selective isotype deficiency is under the control of at least two genes: a background gene and anH-2-linked gene. Responses ofH-2 recombinant B10 strains map theH-2-linked gene to theI-E subregion. Evidence is presented for complementation betweenH-2 and non-H-2 genes in the determination of the low responder phenotype. Low responsiveness appears to be inherited as a dominant trait. Possible functions of the two series of genes are discussed in relation to suppressor mechanisms.     

Chloroplast DNA study of the generaAmbrosia s.l. andHymenoclea (Asteraceae): Systematic implications

The relationship ofAmbrosia (ragweed) andFranseria has long been debated. Their treatment as separate genera has been repeatedly challenged. In this study, chloroplast DNA restriction site variation was examined for species from bothAmbrosia andFranseria as well as taxa from the closely related genusHymenoclea. The chloroplast genomes of members of these three genera were examined using 21 restriction endonucleases and the restriction mutations were used to construct phylogenetic trees. Wagner and Dollo parsimony as well as weighted parsimony were employed to compare the different phylogenies. The results support a close relationship betweenAmbrosia andFranseria, but indicate that the two groups are well separated. Compared toFranseria, Ambrosia is a much more strongly supported group, and the results indicate thatHymenoclea is closer toFranseria than toAmbrosia. The cpDNA phylogeny was used as a framework to examine evolutionary trends in morphology and secondary chemistry.     

Genetic analysis of theT-H-2 region in non-t Chromosomes

A general breeding protocol useful in the construction of congenic lines of mice disparate in the 15 cMT-H-2 region of chromosome 17 in non-t chromosomes is described. Two such congenic lines, B6.TC2/Rn and B6.TC3/Rn, were derived from the C57BL/6J and B6.C-H-2 ^d/By strains using this protocol. Both B6.TC2 and B6.TC3 dissociate the quantitative activity locus for glyoxalase I (Qglo-1) from theH-2 complex, and hence possess BALB/cBy DNA centromeric toH-2. However, neither new strain is able to map anyH-2-associated restriction fragment length polymorphism with anH-2 cDNA probe even though both strains are recombinant in the 2 cMQglo-1-H-2K interval.     

Selective reversal of H-2 linked genetic unresponsiveness to lysozymes

Genes outside of the mouse major histocompatibility complex (H-2) were found to be capable of specifically reversing the previously described nonresponsiveness to hen egg-white lysozyme (HEL) owing to H-2 ^b immune response (Ir) genes. C3H.SW, BALB.B, and C57L, all of the H-2 ^b haplotype, showed responsiveness to HEL, but not to human lysozyme (H UL). Mapping of the reversing gene(s) was attempted by testing H-2 ^b recombinant inbred (RI) strains of mice carrying C3H, BALB, and C57L non-H-2 ^b genes. Analysis of the strain distribution pattern of responsiveness with both CXB and BXH RI strains was consistent with the location of the responsible site within the H-3 region on chromosome 2. The anti-HEL proliferative responsiveness in two H-3 congenic strains of mice, B10.C(28NX) ^SN and B10.C-H-3 ^{cH-3 a} , that have BALB/c genes within the H-3 region confirmed the mapping, as well as localized the reversing gene(s) near the Ir-2 gene. The data are discussed with regard to the site of expression of the reversing gene(s) and its mechanism of action.Abbreviations used in this paper MHC major histocompatibility complex - HEL hen egg-white lysozyme - Ir immune response gene - HUL human lysozyme - SDP strain distribution pattern - PFC plaque-forming cells; ₂ m, ₂-microglobulin - CFA complete Freund's adjuvant - PT-LN parathymic lymph nodes - RI recombinant inbred mice     

H-2 typing of mutants of thet 6 haplotype in the mouse

Mutantt haplotypes derived from thet ⁶ haplotype were typed forH-2. The mutantt ^h2 that arose fromt ⁶ due to crossing over in the region betweenT andtf had, as expected, lost theH-2 haplotype characteristic oft ⁶. The haplotypest ^h17,t ^h18, andt ^p1, which also arose by recombination, but which represent the complementary crossover products, including the distal part of thet ⁶ haplotype, carried the sameH-2 type ast ⁶. This suggests that crossing over betweentf andH-2 is suppressed int ^h17 andt ¹⁸. This in turn suggests that mutantt haplotypes suppress crossing over for that part of thet chromatin that they still retain.The origin oft ^h7, which apparently did not include any crossover distal toT, and which retains the crossover-suppressing property oft ⁶, retains thet ⁶ H-2 type. Unexpectedly, J ^h20 , which expressestf and was at first thought to have arisen due to crossing over, also retains theH-2 type oft ⁶. This provides part of the evidence thatt ^h20 arises fromt ⁶ not by crossing over, but by a small deletion, and hence that duplication and deletion are possible modes of origin of mutantt haplotypes.Abbreviations used in this paper are t haplotype mutant haplotype of the chromosome 17, often designated J allele - T Brachyury mutant - T/+ short-tailed mouse - T/T lethal during embryogenesis - T-int T interaction (characteristic oft haplotypes that interact in heterozygotes withT to produce a tailless mouse) - tf locus homozygotes showing waves of hair loss - Kb knobby, which produces a knobbly tailed heterozygote, homozygous lethal - titer reciprocal of serum dilution giving 50% kill     

A new locus (H-2T) at theD end of theH-2 complex

A.TH (H-2 ^t2) anti-A.TL (H-2 ^t1) effectors, obtained after in vitro restimulation of in vivo sensitized cells, react in the CML assay not only withH-2 ^t1, but also with a number of other targets carrying unrelatedH-2 haplotypes. The broad cross-reactivity can be explained by postulating the presence among the effectors of at least two populations of cells, one reacting with antigens controlled by theI region, and the other directed against antigens controlled by a locus at theD end, outside theH-2 complex. The existence of the two cell populations is also supported by cold-target inhibition data. The locus coding for the D-end CML antigens maps betweenQa-2 andTla. The locus is assigned the symbolH-2T. TheH-2T-locus CML is seen only after in vivo presensitization, but the killing is not K/D-restricted.     

Immune response deficiency of BSVS mice

The genetic control of the low response of BSVS mice to streptococcal Group A carbohydrate (GAC) was studied in crosses with responder A/J mice. F₁ mice were responders. In the backcross (BSVS × A/J)F₁ × BSVS mice, there were equal numbers of anti-GAC responder and nonresponder mice, indicating genetic control by a small number of major loci. The anti-GAC responses of the backcross mice showed no obligate linkage between responder status and A/JH-2 orIgC _H alleles. However, it was observed that the average anti-GAC titers were higher in backcross mice heterozygous at these loci. The above data, a lack of low-responder F₂ animals, and the segregation of a non-H-2-, non-IgC _H -linked locus in the first and second backcross mice, indicate that the defect in the BSVS anti-GAC responsiveness involves three loci: one linked toH-2, another linked toIgC _H , and a third locus —tentatively namedIr-GAC- not linked toH-2, IgC _H , orHbb.     

Eine neueThomsonia-Art (Araceae) aus Thailand

A new species,Thomsonia sumawongii Bogner, is described from Thailand. Relationships toTh. napalensis and betweenThomsonia, Pseudodracontium andAmorphophallus are discussed.Allopythion hookeri Schott has to be eliminated as dubious.

     

Location of the structural gene for glycyl ribonucleic acid synthetase by means of a strain ofEscherichia coli possessing an unusual enzyme

Summary E. coli KB (Benzer) differs from other common laboratory strains in possessing a glycyl sRNA synthetase with a 50 to 100 times elevated K _m for glycine. The degree of charging of glycyl sRNA in this strain can be increased by supplementing the growth medium with glycine. The altered enzyme has been used as a marker by which to map its structural gene. Linkage analysis of recombinants from uninterrupted matings, and cotransduction (80%) of the synthetase withxyl, indicate that this gene is located betweenxyl andmalt, close toxyl, at min 69.5 on the map drawn byTaylor andThoman (1964).     

Numerical taxonomy of some species of hypoxylon

Numerical analysis has resulted in a division of the coloured and non-coloured species ofHypoxylon. It is suggested that the coloured papillate species e.g.H. multiforme are more closely related toH. fragiforme and members of the Hypoxylon section than to non-coloured papillate species as indicated in the current classification of the genus.The relationships betweenHypoxylon, Daldinia andRosellinia are discussed.