The effect of Lr19-translocation on in vitro androgenesis and inheritance of leaf-rust resistance in DH3 lines and F2 hybrids of common wheat

Leaf-rust resistance and androgenesis were studied in the anther cultures of Triticum aestivum L., which included Saratovskaya 29 cultivar, the isogenic line Ps29, and three F1 hybrids (L503/S55, L504/S58, ATS7/L1063) with 7DS-7DL-7Ae#1L translocation of Lr19 gene (Lr19 translocation) from Agropyron elongatum (Host) P.B. The Lr19 translocation was shown to affect the induction of embryogenesis and green plant regeneration. The frequencies of Lr19 translocation differed in F2 hybrids obtained by traditional hybridization and in sets of DH lines obtained in F1 anther cultures derived from the same combinations of T. aestivum parental forms. The number of leaf-rust resistant genotypes tended to decrease. The frequency of Lr19 translocation in the set of DH3 lines derived from F1 L504/S58 was significantly lower than in other sets of DH3 lines and F2 hybrid populations.     

A complex balanced chromosomal rearrangement in repeated abortions

Summary A double balanced reciprocal translocation involving four chromosomes, t(1;19;6;14) (1p11; 19p11; 6q25; 14q21), was found in the phenotypically normal husband in a couple referred because of repeated abortions. Reciprocal translocations, t(6;14), had been transmitted by his mother, his father being apparently homozygous for a translocation comprising pairs 1 and 19-t(1;19)(1;19). The genetic consequences of this complex chromosomal rearrangement are analyzed.     

A new variant translocation (19q plus, 22q minus) in chronic myelocytic leukemia

A translocation between chromosome 19 and chromosome 22 was found in one out of nine patients with CML. All the remaining eight patients demonstrated a translocation between chromosomes 9 and 22. The clinical pattern of the disease was similar in the patient with the translocation between chromosomes 19 and 22 and in the other CML patients. Thus the presence of the Ph¹ chromosome appears to be more important for the course and pattern of the disease than the location of the translocated fragment.     

Analysis of the “Poso” wheat translocation

The two translocation chromosomes in the Poso 5B/7B translocation have been isolated in separate heterozygous aneuploid stocks (19^II+5B+T). The translocation breakpoints are in the long arm of chromosome 7B and the short arm of chromosome 5B. The translocation chromosome bearing the 5B^L pairing inhibitor was obtained as a homozygous aneuploid (19^II+T ₁ ^II ). The heterozygous aneuploid hemizygous for the pairing inhibitor (19^II+5B+T₂) was used to produce intergeneric hybrids. Only a small percentage were of the high-pairing type (17%), the majority having received chromosome 5B through the egg. This indicates a strong selection against eggs containing the translocation chromosome deficient for the pairing inhibitor.     

Fusion of 9 beta-satellite and telomere (TTAGGG)n sequences results in a jumping translocation

A newborn was found to have an isochromosome for the short arm of chromosome 9, i(9p) and a jumping translocation of the whole long arm. In 94.4% metaphases, 9q was fused to the telomere of chromosome 19p and, in 5.6% of metaphases, 9q was fused to the telomere of chromosome 8p. The net result was trisomy for the short arm of chromosome 9. With the pan telomere probe, fluorescent in situ hybridization (FISH) investigations found an interstitial telomere on the der(19) and der(8). The 9 beta and classical satellite probes gave a signal only on the long arm of chromosome 9 involved in the jumping translocation. The 9 alpha satellite probe hybridized to i(9p) and not to the other derivative chromosomes. A combination of chromosome 9 (red) and chromosome 19 (green) paint probes used to rapidly screen metaphases for the jumping translocation found 88 metaphases had a der(19)t(9;19) and 4metaphases had a der(8)t(8;9). For the first time, the junction of a jumping translocation has been shown to involve the telomere sequence (TTAGGG)n and beta-satellite sequences by FISH. In this paper, we also review the simultaneous occurrence of an isochromosome for the short arm and translocation of the whole long arm and constitutional jumping translocations.     

NOTCH2 Is Neither Rearranged nor Mutated in t(1;19) Positive Oligodendrogliomas

The combined deletion of 1p and 19q chromosomal arms is frequent in oligodendrogliomas (OD) and has recently been shown to be mediated by an unbalanced t(1;19) translocation. Recent studies of 1p/19q co-deleted OD suggest that the NOTCH2 gene is implicated in oligodendrocyte differentiation and may be involved in this rearrangement. The objective of the present study was to analyze the NOTCH2 locus either as a chromosomal translocation locus that may be altered by the 1p/19q recurrent rearrangement or as a gene that may be inactivated by a two hit process. We performed an array-CGH analysis of 15 ODs presenting 1p/19q co-deletion using a high-density oligonucleotide microarray spanning 1p and 19q pericentromeric regions with 377 bp average probe spacing. We showed that the 1p deletion extends to the centromere of chromosome 1 and includes the entire NOTCH2 gene. No internal rearrangement of this gene was observed. This strongly suggests that the t(1;19) translocation does not lead to an abnormal NOTCH2 structure. The analysis of the entire NOTCH2 coding sequence was performed in four cases and did not reveal any mutation therefore indicating that NOTCH2 does not harbor genetic characteristics of a tumor suppressor gene. Finally, the detailed analysis of chromosome 19 pericentromeric region led to the identification of two breakpoint clusters at 19p12 and 19q11–12. Interestingly, these two regions share a large stretch of homology. Together with previous observations of similarities between chromosome 1 and 19 alphoid sequences, this suggests that the t(1;19) translocation arises from complex intra and interchromosomal rearrangements.This is the first comprehensive deletion mapping by high density oligo-array of the 1p/19q co-deletion in oligodendroglioma tumors using a methodological approach superior to others previously applied. As such this paper provides clear evidence that the NOTCH2 gene is not physically rearranged by t(1;19) translocation of oligodendroglioma tumors.     

Akt activation is required at a late stage of insulin-induced GLUT4 translocation to the plasma membrane

Insulin stimulates the translocation of glucose transporter GLUT4 from intracellular vesicles to the plasma membrane (PM). This involves multiple steps as well as multiple intracellular compartments. The Ser/Thr kinase Akt has been implicated in this process, but its precise role is ill defined. To begin to dissect the role of Akt in these different steps, we employed a low-temperature block. Upon incubation of 3T3-L1 adipocytes at 19 C, GLUT4 accumulated in small peripheral vesicles with a slight increase in PM labeling concomitant with reduced trans-Golgi network labeling. Although insulin-dependent translocation of GLUT4 to the PM was impaired at 19 C, we still observed movement of vesicles toward the surface. Strikingly, insulin-stimulated Akt activity, but not phosphatidylinositol 3 kinase activity, was blocked at 19 C. Consistent with a multistep process in GLUT4 trafficking, insulin-stimulated GLUT4 translocation could be primed by treating cells with insulin at 19 C, whereas this was not the case for Akt activation. These data implicate two insulin-regulated steps in GLUT4 translocation: 1) redistribution of GLUT4 vesicles toward the cell cortex-this process is Akt-independent and is not blocked at 19 C; and 2) docking and/or fusion of GLUT4 vesicles with the PM-this process may be the major Akt-dependent step in the insulin regulation of glucose transport.     

Human telomeric 6; 19 translocation chromosome with a tendency to break at the fusion point

The behavior of a translocation chromosome t(6; 19) in the lymphocytes of a mentally retarded woman with other anomalies has been analyzed. The two chromosomes were attached at the telomeres of their short arms without any apparent deletion. The centromere of chromosome 19 was marked by a primary constriction and the site of the centromere of chromosome 6 by a C-band, but no constriction. The translocation chromosome showed two primary constrictions once in 8,800 metaphases, probably resulting from mitotic crossing-over. One or both chromatids of the translocation chromosome were broken at the attachment point with a frequency of 1/733 cells. In addition, the chromosome was often bent at this point and the translocated chromosomes 19 and 6 showed a differential spiralization. In this characteristic as well as the weakness of the fusion point, this chromosome differed from other translocations; the fusion obviously was not as firm as in translocations in general. The broken-off chromosome 6 did not regain a primary constriction, but had the appearance of a large acentric fragment. The segregation of the translocation chromosome and the fragment gave rise to a complicated mosaicism with various levels of ploidy for the fragment lacking a functional centromere. The data are in quantitative agreement with the equilibrium expectations under the assumption that each fragment goes to either pole at random in mitosis and that cells divide at the same rate regardless of ploidy. The high rate of nondisjunction of the fragment showed that the inactivated centromere of the translocation chromosome did not regain its activity when chromosome 19 with the functional centromere became separated from it. — The fragility and the behavior of the translocation chromosome and the production of telomeric associations are briefly discussed.     

Segregation of two independent chromosomal translocations in one family

Summary A family with two independent reciprocal translocations t(3;19) and t(16;22) is described. The proband, a 4-week-old male, was phenotypically conspicious with multiple congenital anomalies. Cytogenetic examination revealed a balanced reciprocal translocation (3;19) and a supernumerary small marker chromosome. His mother carried two balanced reciprocal translocations, the one found in the proband and a reciprocal translocation (16;22). The maternal grandmother and a maternal uncle were identified as carriers of a single translocation (16;22). The findings in the family members permitted the identification of the proband's marker chromosome as a derivative chromosome 22 resulting in partial trisomy 16 and 22.     

The influence of combinations of alien translocations on in vitro androgenesis in near-isogenic lines of spring bread wheat

The features of in vitro androgenesis were studied in cultured anthers of spring bread wheats L503 and Dobrynya, having 7DS-7DL-7Ae#1L translocation with genes Lr19/Sr25 (Lr19 translocation) from Agropyron elongatum (Host.) P.B. and their near-isogenic lines carrying combinations of Lr19 translocation with translocations: 1BL-1R#1S with genes Pm8/Sr31/Lr26/Yr9 (Lr26 translocation) from Secale cereale L., 4BS-4BL-2R#1L with genes Lr25/Pm7 (Lr25 translocation) from Secale cereale, 3DS-3DL-3Ae#lL with genes Lr24/Sr24 (Lr24 translocation) from Agropyron elongatum and 6BS-6BL-6U#1L with gene Lr9 (Lr9 translocation) from Aegilops umbellulata Zhuk. In comparison with those varieties having received the Lr19 translocation, the following was established: (1) the combination of translocations Lr19 + 26 increased embryo frequency and green plant regeneration; (2) the combination of translocations Lr19 + 9 decreased embryo frequency but increased green plant regeneration; (3) the combination of translocations Lr19 + 24 decreased embryo frequency but increased green and albino plant regeneration; (4) the combination of translocations Lr19 + 25 increased embryo frequency and green plant regeneration but decreased albino plant regeneration. Thus, on near-isogenic lines of spring bread wheat, the influences of genotypes of four alien translocation combinations on in vitro androgenesis were determined.     

The Effect of Lr19-Translocation on in Vitro Androgenesis and Inheritance of Leaf-Rust Resistance in DH3 Lines and F2 Hybrids of Common Wheat

Leaf-rust resistance and androgenesis were studied in the anther cultures of Triticum aestivum L., which included Saratovskaya 29 cultivar, the isogenic line Ps29, and three F₁ hybrids (L503/S55, L504/S58, ATS7/L1063) with 7DS-7DL-7Ae#1L translocation of Lr19 gene (Lr19 translocation) from Agropyron elongatum (Host.) P.B. The Lr19 translocation was shown to affect the induction of embryogenesis and green plant regeneration. The frequencies of Lr19 translocation differed in F₂ hybrids obtained by traditional hybridization and in sets of DH₃ lines obtained in F₁ anther cultures derived from the same combinations of T. aestivum parental forms. The number of leaf-rust resistant genotypes tended to decrease. The frequency of Lr19 translocation in the set of DH₃ lines derived from F₁ L504/S58 was significantly lower than in other sets of DH₃ lines and F₂ hybrid populations.     

Mea2/Golga3 gene is disrupted in a line of transgenic mice with a reciprocal translocation between Chromosomes 5 and 19 and is responsible for a defective spermatogenesis in homozygotes

A line of transgenic mouse T604 transmitted a transgene to progeny together with a set of chromosomes with a reciprocal translocation. The transgene was integrated at a single site in the translocated chromosomes, as revealed by fluorescence in situ hybridization. The transgenic hemizygous males, also heterozygous for the translocation of chromosomes, showed apparently normal spermatogenesis, while the males homozygous for the transgene as well as for the translocated chromosomes showed a defect in spermatogenesis. Considering that the genetic rearrangement by either insertion of the transgene or the chromosome translocation in the T604 mouse line might have caused a recessive mutation in a gene indispensable for spermatogenesis, we have mapped the transgene integration site and the translocation breakpoints in mouse chromosomes. Linkage analysis with SSLP markers showed that the loci for the transgene and the translocation breakpoints were closely located to D5Mit24 on Chromosome (Chr) 5, and to a region between D19Mit19 and D19Jpk2 on Chr 19. Mea2 gene, mapped only 2 cM from D5Mit24 and known to show male-specific enhanced expression in the testis, was analyzed as a candidate for the gene disrupted in T604 transgenic mice. Southern blot analysis revealed that Mea2 gene was indeed disrupted in T604 mice, and Northern blot analysis of the testis RNA showed that the expression of Mea2 was annihilated in the testis of T604 transgenic homozygotes. Received: 8 July 1998 / Accepted: 23 September 1998     

A new centric fusion translocation in cattle: rob (13;19)

A new Robertsonian translocation has been found in cattle. A bull from Marchigiana breed (central Italy) was found to be a heterozygous carrier of a centric fusion translocation involving cattle chromosomes 13 and 19 according to RBA-banding and cattle standard nomenclatures. CBC-banding revealed the dicentric nature of this new translocation, underlining the recent origin of this fusion. In fact, both the bull's parents and relatives had normal karyotypes. In vitro fertilization tests were also performed in the bull carrying the new translocation, in two bulls with normal karyotypes (control) and in four other bulls carrying four different translocations.     

A physical map of the Thinopyrum-derived Lr19 translocation.

Twenty-nine lines with deletions in the Lr19 ('Indis') translocated chromosome segment were used to physically map three Thinopyrum RFLP loci as well as the Sr25 and Sd1 loci. From the data, the relative locations of marker loci on the translocation were determined as: Sd1, Xpsr165, Xpsr105, Xps129, Lr19, Wsp-D1, Sr25/Y. The data confirmed the reported homoeology between the Lr19 segment and chromosome arm 7DL of wheat. Also, it seems that the Lr19 translocation in 'Indis' is very similar to the Lr19 segment in the T4 source and that the former may not derive from Thinopyrum distichum. Key words : deletion mapping, leaf rust resistance.     

Cytogenetic studies in an acute leukemia patient following cerebellar astrocytoma

Summary Acute, monomyelogenous leukemia (AMML) was diagnosed in a patient with a derived 13;14 translocation and prior treatment for a cerebellar astrocytoma. A bone marrow aspirate at the time of diagnosis of leukemia showed abnormalities of chromosome 11, 12 and 16 in addition to the constitutional aberration. The patient's mother carried the same 13;14 translocation, as did 2 siblings, a maternal uncle, and four of his six children. The father had a reciprocal translocation between numbers 1 and 19 which was incidental to the present study.     

The topogenic contribution of uncharged amino acids on signal sequence orientation in the endoplasmic reticulum

Signal sequences for insertion of proteins into the endoplasmic reticulum induce translocation of either the C- or the N-terminal sequence across the membrane. The end that is translocated is primarily determined by the flanking charges and the hydrophobic domain of the signal. To characterize the hydrophobic contribution to topogenesis, we have challenged the translocation machinery in vivo in transfected COS cells with model proteins differing exclusively in the apolar segment of the signal. Homo-oligomers of hydrophobic amino acids as different in size and shape as Val(19), Trp(19), and Tyr(22) generated functional signal sequences with similar topologies in the membrane. The longer a homo-oligomeric sequence of a given residue, the more N-terminal translocation was obtained. To determine the topogenic contribution of all uncharged amino acids in the context of a hydrophobic signal sequence, two residues in a generic oligoleucine signal were exchanged for all uncharged amino acids. The resulting scale resembles a hydrophobicity scale with the more hydrophobic residues promoting N-terminal translocation. In addition, the helix breakers glycine and proline showed a position-dependent effect, which raises the possibility of a conformational contribution to topogenesis.     

Sperm chromosome analysis of two men heterozygous for reciprocal translocations: t(1;9)(q22;q31) and t(16;19)(q11.1;q13.3).

Sperm chromosome complements were analysed in two men who were heterozygous carriers of reciprocal translocations. A total of 363 sperm were karyotyped after in vitro penetration of hamster oocytes, including 180 sperm from a male with a t(1;9)(q22;q31) and 183 from a male with a t(16;19)(q11.1;q13.3). All possible 2:2 and 3:1 meiotic segregations were observed for both translocations. The frequencies of alternate, adjacent 1, adjacent 2, and 3:1 segregations were 46%, 38%, 13%, and 4% for the t(1;9) and 40%, 28%, 31%, and 1% for the t(16;19), respectively. Within the alternate segregation group, the number of normal sperm was not significantly different from the number of sperm carrying a balanced form of the translocation for either of the translocations, as expected. There was no evidence for an interchromosomal effect of either translocation, since the frequencies of numerical abnormalities unrelated to the translocation were within the normal range observed in sperm from control donors. The percentage of sperm with an unbalanced form of the translocation was 54% for the t(1;9) and 61% for the t(16;19).     

Robertsonian chromosome polymorphism in the Arabian oryx (Oryx leucoryx)

A Robertsonian translocation was found in a herd of Arabian oryx (Oryx leucoryx). The translocated chromosome, when analyzed by G-banding, seemed to involve the fusion of chromosomes 17 and 19. The results of C-banding suggested that the fused chromosome is dicentric. The translocation was traced back through two generations and occurred in a total of 8 of 62 animals in the herd.     

Poor prognosis of acute lymphoblastic leukemia with translocation (1;19) in childhood: potential interest of allogeneic bone marrow transplantation

We report a new case of childhood acute lymphoblastic leukemia with translocation (1;19). At the time of diagnosis, the only adverse prognosis factor was the existence of this translocation. Under conventional chemotherapy, the girl experienced early marrow relapse (duration of first remission was 2 months). She received allogeneic bone marrow transplantation during the second remission and is alive in continuous complete remission 20 months after transplant. Several earlier reports have suggested that children with the (1;19) have a poor prognosis; If this poor response to conventional therapy is confirmed, an allogeneic bone marrow transplantation should be considered during the first remission.