Differential polyteny and polyploidy in diaspine coccids (Homoptera: Coccoidea)

Hughes‐Schrader, Sally

doi:10.1007/bf01259529

Cited by 23 publications

(3 citation statements)

References 10 publications

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“…The data are par ticularly convincing in the case of Drosophila polytene chromosomes, where these fibers hybridize in situ with a telomere-specific probe (Rubin 1978). Intriguingly, in rare preparations of somatic nuclei of the coccid Chiysomphalus ficus and of onion and other plant spe cies, all of the chromosomes appear linked together at their ends to form a continuous chain or "spireme" (Hughes-Schrader 1957;Wagenaar 1969).…”

mentioning

confidence: 71%

UbcD1, a Drosophila ubiquitin-conjugating enzyme required for proper telomere behavior.

Cenci¹,

Rawson²,

Belloni³

et al. 1997

Genes Dev.

121

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The end-to-end association of chromosomes through their telomeres has been observed in normal cells of certain organisms, as well as in senescent and tumor cells. The molecular mechanisms underlying this phenomenon are currently unknown. We show here that five independent mutant alleles in the Drosophila UbcDl gene cause frequent telomere-telomere attachments during both mitosis and male meiosis that are not seen in wild type. These telomeric associations involve all the telomeres of the D. melanogaster chromosome complement, albeit with different frequencies. The pattern of telomeric associations observed in UbcDl mutants suggests strongly that the interphase chromosomes of wild-type larval brain cells maintain a Rabl orientation within the nucleus, with the telomeres and centromeres segregated to opposite sides of the nucleus. The UbcDl gene encodes a class I ubiquitin-conjugating (E2) enzyme. This indicates that ubiquitin-mediated proteolysis is normally needed to ensure proper telomere behavior during Drosophila cell division. We therefore suggest that at least one of the targets of UbcDl ubiquitination is a telomere-associated polypeptide that may help maintain proper chromosomal orientation during interphase.

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mentioning

confidence: 71%

UbcD1, a Drosophila ubiquitin-conjugating enzyme required for proper telomere behavior.

Cenci¹,

Rawson²,

Belloni³

et al. 1997

Genes Dev.

121

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“…Though it is not known how homologous chromosomes are located in relation to each other it is believed that they are most likely to lie adjacent to each other in the chain and so facilitate pairing in meioticprophases. Chain-like end-to-end chromosome associations in somatic and germ line mitoses have been observed in certain male coccids by Hughes- Schrader (1957) •-a secondary pairing which she suggests may act as a stabilising factor. If terminal attachment does occur in the triploid Listroderes, then it cannot facilitate pairing for at no time has any true synaptic behaviour been observed.…”

Section: The Prophase Of Maturationmentioning

confidence: 92%

3.—The Cytology of the Parthenogenetic Australian Weevil Listroderes costirostris Schönh

Sanderson

1973

Trans. R. Soc. Edinb.

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SynopsisKaryograms prepared from ovarian and blastoderm cells of the parthenogenetic Australian Brown Vegetable Weevil demonstrate a consistent triploid condition with 30 chromosomes which can be grouped into 10 sets of homologues. Meiosis is replaced by a single mitotic-like division in which 30 univalent chromosomes, each composed of two chromatids, divide equationally between an ootid nucleus and a single polar nucleus. Prior to the differentiation of the oocytes a peculiar bouquet stage occurs in the cells of the end chamber of each ovariole, but the significance of this phase is not known. Arrested development in eggs from individuals of low fertility is investigated and the relationship of body size and chromosome number is discussed.

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“…Cytological studies of cl~romosome number and morphology and photometric studies of nuclcar D N A contcnt have provided such cvidence (Hughes-Schradcr, 1957;Hughcs-Schrader and Schrader, 1956;Schrader, 1956). Hughes-Schrader (1940) studied meiosis in Llnveiella tneszechszia, a Henlipteran, and reported tertiary and occasional quarternary splits in chromosomes at the sccond nleiotic division, resulting in obvious half and quarter chromatids.…”

Section: Aslnlysis Of the Labeli~zg Pattel-nmentioning

confidence: 96%

Pattern of Segregation of Labeled Dna at the Chromatid Level of Chromosomes With Diffuse Centromeres

Nelson¹

1969

Can. J. Genet. Cytol.

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After pulse labeling IL7~zzdln pzlr/litrrn shoot meristems \vith "H-thymidine, the cell cycle and its subdivisions \\rere determined autoradiographically using the labeled mitoses method. T h e cycle time was 20 hr. GI = 4.3 hr; C = 9.5 hr; G, = 2.9 hr; and A4 = 3.3 hr. In subsequent experiments seedlings were labeled for 4 t o 5 hr, long enough to label the chron~osomcs' full lengch, eliminating problems associated with asynchronous DhTA replication. T h e longer labeling period did not alter the cell cycle parameters.Cells were designated as being in the first or second division after labeling by the time from the midpoint of the labeling period. Seedlings were placed in 0.1% cycloheximide solution to cause sister chromatids in metaphase cells to separate from each other. Autoradiographs were then made to determine segregation of labeled D N A at the chromatid level. A t the first division after labeling all chromatids appearcd to be labeled. A t the second division after labcling \\.it11 "H-thymidine the labcling pattern was consistent \\.it11 serniconscrvative segregation of labeled D N A and with sister chromatid exchange.These results are discussed in relation to cytological and photometric studies on chromosome strandedness in L71-rrIn and in other organisms with chromosomes \\it11 diffuse ccntronlcrcs.

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Differential polyteny and polyploidy in diaspine coccids (Homoptera: Coccoidea)

Cited by 23 publications

References 10 publications

UbcD1, a Drosophila ubiquitin-conjugating enzyme required for proper telomere behavior.

UbcD1, a Drosophila ubiquitin-conjugating enzyme required for proper telomere behavior.

3.—The Cytology of the Parthenogenetic Australian Weevil Listroderes costirostris Schönh

Pattern of Segregation of Labeled Dna at the Chromatid Level of Chromosomes With Diffuse Centromeres

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