Chromomeres and Genes

Beermann, Wolfgang

doi:10.1007/978-3-540-37164-9_1

Cited by 121 publications

(54 citation statements)

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“…Because gene activity in polytene chromosomes of 3rd instar larval salivary glands is manifested in the form of discrete swellings known as puffs [9], gene activity can be observed as puffing activity in the light microscope after squashing salivary glands and staining polytene chromosomes. The locations of puffs are given in the nomenclatural system of Bridges for polytene chromosome band regions [lo].…”

Section: Ecdysteroid Regulated Gene Expression and Puffimentioning

confidence: 99%

Ecdysteroid‐regulated gene expression in Drosophila melanogaster

Pongs

1988

European Journal of Biochemistry

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It is a generally accepted paradigm that development of multicellular organisms depends upon morphogenetic signals between cells that instruct changes in gene expression. One well known morphogen is the insect steroid hormone 20-hydroxyecdysone [l]. More particularly, the titer of this steroid hormone in the haemolymph controls in Drosophila melanogaster larvae the onset of their metamorphosis, i. e. death of larval cells and development of imaginal disc cells into adult tissues [2-41. Changes in gene expression in response to 20-hydroxyecdysone have been investigated thoroughly in one larval tissue, the salivary glands of 3rd instar larvae of D . n~elanogaster. The mode of action of 20-hydroxyecdysone in salivary glands was studied first at a cytological [5, 61 and subsequently at a molecular level [7, 81. Ecdysteroid regulated gene expression and puffiBecause gene activity in polytene chromosomes of 3rd instar larval salivary glands is manifested in the form of discrete swellings known as puffs [9], gene activity can be observed as puffing activity in the light microscope after squashing salivary glands and staining polytene chromosomes. The locations of puffs are given in the nomenclatural system of Bridges for polytene chromosome band regions [lo]. The pattern of puffing activity in the polytene chromosomes changes upon an increase of 20-hydroxyecdysone in the haemolymph. The transition from the intermoult puffing pattern to the late larval/prepupal puffing cycle can be induced in vitro by incubating dissected salivary glands of appropriate intermoult larvae with 20-hydroxyecdysone [I I]. The entire late larval/ prepupal puffing cycle involves the sequential as well as temporal activation by 20-hydroxyecdysone of at least 125 puffs, that is of many different genes probably [5, 111. In general, three different responses to 20-hydroxyecdysone have been observed in puffing activity. (a) A number of puffs regress (e.g. at 68C on the left arm of the third chromosome). (b) Some puffs are activated very rapidly, within 5 min (e.g. at 2B5 on the X chromosome, 74EF, and 75B on the left arm of the third chromosome). These puffs have been termed 'early at 22C on the left arm of the second chromosome, and at 82F on the right arm of the third chromosome). These puffs have been termed 'late puffs'. Some of the 125 hormone-regulated puffs express related products, e.g. glue proteins [12]. 20-Hydroxyecdysone might, therefore, be considered a pleiotropic morphogen which resets for metamorphosis in time and space entire networks of cellular activities, not only the expression of one or another solitary gene of key cellular function. Genetics of genes in early puffsCertain early puffs stand out, because it has been found that their activities are required for the induction of most late puffs [13, 141. These puffs are located at 2B-5 at the tip of the X chromosome and at 74EF and 75B on the left arm of the 3rd chromosome. Non-pupariating mutants (npr) have been isolated for the 2B-5 locus [15]. The phenotype of npr-animals is ...

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Section: Ecdysteroid Regulated Gene Expression and Puffimentioning

confidence: 99%

Ecdysteroid‐regulated gene expression in Drosophila melanogaster

Pongs

1988

European Journal of Biochemistry

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“…Therefore, endocycle retains the cyclic expression of several components and regulators of the mitotic cell division machinery. It seems to be of importance that the degree of polytene structure widely varies, and three main types may be distinguished: (1) classic polyteny with characteristical band structure, for example, in the salivary glands of Diptera (Beermann, 1972;Kiknadze et al, 1976;Zhimulev, 1992); (2) the cell with uncomplete expression of polytene features, for example, in the giant trophoblast cells (Zybina, Zybina, 1996, in the suspensor of higher plants (Nagl, 1978(Nagl, , 1981, in trophocytes of insect ovaries (Dej, Spradling, 1999), and in various endocycles of Invertebrata (Nagl, 1978); (3) the cells, in which the polytene features are not revealed, and polyteny may be suggested basing on the multifold DNA replication in the absence of mitosis (Brodsky, Uryvaeva, 1985). At present it is considered that morphological and functional features of the classical polytene chromosomes are accounted for by the following factors.…”

Section: Polytenymentioning

confidence: 99%

Cell Cycle Modification in Trophoblast Cell Populations in the Course of Placenta Formation

Zybina¹,

Zybina²

2011

DNA Replication and Related Cellular Processes

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“…Polytene interphase chromosomes due to chromatid 66 amplification and restricted 3D folding represent a formidable example for such a cis-organization of 67 domains. Microscopic preparations of such chromosomes reveal an organized and reproducible 68 pattern of compacted chromomeres (bands) interrupted by less compacted interband domains 69 (Painter 1934;Beermann 1972). The difference in chromatin compaction was established by 70 cytophotometry (Beermann 1972) and EM dry mass determination (Laird 1980 1977).…”

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confidence: 99%

“…Microscopic preparations of such chromosomes reveal an organized and reproducible 68 pattern of compacted chromomeres (bands) interrupted by less compacted interband domains 69 (Painter 1934;Beermann 1972). The difference in chromatin compaction was established by 70 cytophotometry (Beermann 1972) and EM dry mass determination (Laird 1980 1977). This view was challenged by the limited coding capacity of interbands estimated to represent 74 only ~5% of the total genome (Beermann 1972; however compare Laird 1980) and by the 75 observation, that many of the RNA-polymerase molecules found in interbands are not 76 transcriptionally engaged but are in a paused state (Weeks et al 1998).…”

mentioning

confidence: 99%

“…The difference in chromatin compaction was established by 70 cytophotometry (Beermann 1972) and EM dry mass determination (Laird 1980 1977). This view was challenged by the limited coding capacity of interbands estimated to represent 74 only ~5% of the total genome (Beermann 1972; however compare Laird 1980) and by the 75 observation, that many of the RNA-polymerase molecules found in interbands are not 76 transcriptionally engaged but are in a paused state (Weeks et al 1998). Therefore, interbands were 77…”

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confidence: 99%

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