Conservation of interphase chromatin nonhistone antigens as components of metaphase chromosomes

The degree of conservation of HeLa interphase chromatin nonhistone antigens among the nonhistones of isolated metaphase chromosomes was determined with immunological procedures. Proteins were separated on SDS-polyacrylamide gels and electrophoretically transferred to diazophenylthioether (DPT)-paper, which was then overlaid with antiserum to chromatin from interphase nuclei. The bound antibodies were detected with 125I-labeled protein A. Alternatively, polyacrylamide gels were directly overlaid with antiserum and with 125I-protein A. Densitometry of autoradiograms and stained gels revealed the degree of conservation of nonhistone antigenic determinants from interphase to metaphase to be over 90% for chromatin.     

The chromosomes ofCunninghamia konishii,C. lanceolata,andTaiwania cryptomerioides (Taxodiaceae)

Karyotype analyses were conducted onCunninghamia konishii, Cunninghamia lanceolata, andTaiwania cryptomerioides, all members ofTaxodiaceae. The somatic chromosome number was found to be 2n = 2x = 22 in all species which concurrs with previous reports. The karyotypes are generally asymmetrical with the smaller chromosomes being more submedian than the larger ones. Chromosomes with unusual or specific structures, thought to be associated with the nucleolar organizing region, were found in each species.Cunninghamia species have a marker chromosome pair with an unusually long secondary constriction.Taiwania has an unusually long kinetochore region present in a submedian chromosome pair.     

Mapping of nucleoside phosphorylase (Np-1) and esterase 10 (Es-10) on mouse chromosome 14

A method for detecting two alleles at Np-1 (nucleoside phosphorylase) and three alleles at Es-10 (esterase 10) from mouse blood by cellulose acetate electrophoresis is described. The allelic constitution at these loci for 44 inbred strains and stocks was determined. The location of Np-1 on chromosome 14 was established by backcross experiments in which alleles at Np-1 and Robertsonian translocations were segregating. Es-10 was shown to be linked to Np-1, and the following genetic map of Chr 14 was constructed: centromere-(8.9±4.0 cM)-[Np-1, Wc]-(10.2±1.9 cM)-Es-10-(15.5±3.7 cM)-s. The homologous human loci, NP and ES-D, are not linked.This work was supported by Contract E(11-1)-3267 with the Energy Research and Development Administration, by Contracts NO1-ES4-2156 and NO1-ES4-2159 with the National Institute of Environmental Health Sciences, and by Grants GM 19656 and GM 20919 from the National Institute of General Medical Sciences. D. A. K. was a participant in the 1975 Summer Program for College, Graduate, and Medical Students, which was supported, in part, by the Clark Foundation. The Jackson Laboratory is fully accredited by the American Association for Accreditation of Laboratory Animal Care.     

Human β-glucuronidase: Assignment of the structural gene to chromosome 7 using somatic cell hybrids

-Glucuronidase (GUS) has become an important enzyme model for the genetic study of molecular disease, enzyme realization, and therapy, and for the biogenesis and function of the lysosome and lysosomal enzymes. The genetics of human -glucuronidase was investigated utilizing 188 primary man-mouse and man-Chinese hamster somatic cell hybrids segregating human chromosomes. Cell hybrids were derived from 16 different fusion experiments involving cells from ten different and unrelated individuals and six different rodent cell lines. The genetic relationship of GUS to 28 enzyme markers representing 19 linkage groups was determined, and chromosome studies on selected cell hybrids were performed. The evidence indicates that the -glucuronidase gene is assigned to chromosome 7 in man. Comparative linkage data in man and mouse indicate that the structural gene GUS is located in a region on chromosome 7 that has remained conserved during evolution. Involvement of other chromosomes whose genes may be important in the final expression of GUS was not observed. A tetrameric structure of human -glucuronidase was demonstrated by the formation of three heteropolymers migrating between the human and mouse molecular forms in chromosome 7 positive cell hybrids. Linkage of GUS to other lysosomal enzyme genes was investigated. -Hexosaminidase HEX _B) was assigned to chromosome 5; acid phosphatase₂ (ACP ₂) and esterase A₄ (ES-A ₄) were assigned to chromosome 11; HEX _A was not linked to GUS; and -galactosidase (-GAL) was localized on the X chromosome. These assignments are consistent with previous reports. Evidence was not obtained for a cluster of lysosomal enzyme structural genes. In demonstrating that GUS was not assigned to chromosome 9 utilizing an X/9 translocation segregating in cell hybrids, the gene coding for human adenylate kinase₁ was confirmed to be located on chromosome 9.Supported by NIH Grants HD 05196, GM 20454, and GM 06321, by NSF Grant BMS 73-07072, and by HEW Maternal and Child Health Service, Project 417.     

Karyology and evolution inSesamoides (Resedaceae)

The meiotic behaviour abnormalities, fertility and size of pollen of 6 taxa ofSesamoides have been analysed. Besides diploids (2x), polyploids (4x, 6x, 8x) have been found. The chromosome base number is x = 10, but an origin from x = 5 is suggested.     

Revision of SAT chromosome number in Triticum monococcum with respect to nucleolar organizers activity

Summary Six varieties of Triticum monococcum were analysed by means of the nucleolar test; i.e., estimation of the maximum number of primary nucleoli per nucleus. All of the varieties exhibited 4 primary nucleoli in telophase and early interphase. Following detailed karyological analysis four SAT chromosomes in all six karyotypes were found in accordance with the maximum nucleolar number. Secondary constrictions and microsatellites were localised on the short arms of chromosome pairs 3 and 5. A new order of the chromosomes in the idiogram of Tr. monococcum is proposed.     

Effect of CO2 on short-term human lymphocyte culture in vitro

Summary There was no significant difference in the mitotic indices of the cultures maintained at different CO₂ concentrations, i.e. 0%, 5% and 10%. However, considerable variation was recorded among different individuals. Supported by National Cancer Institute Contract No. 1 CP 43251.     

Esr,a second locus in the house mouse controlling esterase-5

Electrophoretic variation characterized by the presence (ES-5B⁺) or absence (ES-5B^–) of esterase-5B in the plasma of the house mouse has been observed. It is suggested that the expression of esterase-5B is controlled by an autosomal locus, Esr, linked to Ldr-1 on chromosome 6, in addition to the presumptive structural locus Es-5, which is located on chromosome 8. A gene order of Lyt-3-Esr-Ldr-1 was determined by two crosses.Supported by the Deutsche Forschungsgemeinschaft (SFB 46).This is communication No. 33 of a research program devoted to the investigation of cellular distribution and genetics of nonspecific esterases.     

The genetics of phenotypic plasticity. IV. Chromosomal localization

The contributions of each chromosome to the traits thorax size and plasticity of thorax size as affected by temperature in Drosophila melanogaster were measured. A composite stock was created from lines previously subjected to selection on thorax size or plasticity of thorax size. A chromosome extraction was performed against a uniform background lacking genetic variation, provided by a stock of marked balancer flies. With regard to amount of plasticity, chromosome I and the balancer stock showed no plasticity, the composite stock showed the greatest plasticity, and chromosomes II and III were intermediate. Chromosome I showed significant genetic variation for thorax size at both 19° C and 25° C, but not for plasticity, while chromosome II showed significant genetic variation for plasticity, but not for thorax size. Chromosome III showed significant genetic variation for both thorax size and plasticity. We tested the predictions of three models of the genetic basis of phenotypic plasticity: overdominance, pleiotropy, and epistasis. The results support the epistasis model, in agreement with earlier work. The amount of developmental noise was correlated with phenotypic plasticity at 25° C, in agreement with earlier work. A negative correlation was found at 19° C for chromosome II, contrary to earlier work.     

Analysis of a case of somatic instability in a strain of maize from India

A case of somatic instability affecting aleurone colour in a strain of maize from India with flint background was analysed. The somatic instability is localized to theC ¹ (Inhibitor) allele ofC locus on the short arm of chromosome 9. Molecular tests indicated thatAc is not present in the Indian stock and the evidence is consistent with the involvement of theEn (Spm) transposable element in the instability. The presence of theEn (Spm)-like element in the stock would suggest that these elements have been present in the maize genome for a long time. A new allele ofshrunken (sh1) gene with a somewhat unorthodox breeding behaviour is also described.