Genome Activity and Gene Expression in Avian Erythroid Cells

Gasaryan, K.G.

doi:10.1016/s0074-7696(08)61170-5

Cited by 14 publications

(15 citation statements)

References 116 publications

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“…In this regard, we find it interesting that the only cell type identified which contains the ev-3 preintegration site in a nuclease-resistant conformation is 15d RBC. The potential significance of this finding is suggested by the fact that RBC chromatin undergoes considerable condensation during maturation of immature erythroblasts to the more mature erythrocytes analyzed in the work described in this report (16 …”

Section: Discussionmentioning

confidence: 70%

Varied interactions between proviruses and adjacent host chromatin.

Conklin¹,

Groudine²

1986

Mol. Cell. Biol.

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Retroviruses integrated at unique locations in the host genome can be expressed at different levels. We have analyzed the preintegration sites of three transcriptionally competent avian endogenous proviruses (evs) to determine whether the various levels of provirus expression correlate with their location in active or inactive regions of chromatin. Our results show that in three of four cell types, the chromatin conformation (as defined by relative nuclease sensitivity) of virus preintegration sites correlates with the level of expression of the resident provirus in ev+ cells: two inactive proviruses (ev-1 and ev-2) reside in nuclease-resistant chromatin domains and one active provirus (ev-3) resides in a nuclease-sensitive domain. Nuclear runoff transcription assays reveal that the preintegration sites of the active and inactive viruses are not transcribed. However, in erythrocytes of 15-day-old chicken embryos (15d RBCs), the structure and activity of the ev-3 provirus is independent of the conformation of its preintegration site. In this cell type, the ev-3 preintegration site is organized in a nuclease-resistant conformation, while the ev-3 provirus is in a nuclease-sensitive conformation and is transcribed. In addition, the nuclease sensitivity of host sequences adjacent to ev-3 is altered in ev-3+ 15dRBCs relative to that found in 15d RBCs that lack ev-3. These data suggest that the relationship between preintegration site structure and retrovirus expression is more complex than previously described.Avian and murine retroviruses can be expressed at different levels after integration into the host cell genome (2,14,21,26,29). In some cases, this variation is not due to genetic differences between the proviruses but instead is dependent on their site of integration (26,29). Analyses of two mouse mammary tumor virus proviruses acquired by exogenous infection in cultured cells indicated that the differential activity of these proviruses is dependent on their location in nuclease-sensitive or nuclease-resistant regions of the host cell genorne (14). An analogous relationship is not evident, however, for murine viruses introduced into the mouse germ line (Mov proviruses;27,28). In the latter case, inherited proviruses are inactive, even when located in transcriptionally active regions of chromatin (4,20). In contrast to Mov proviruses, some of the naturally occurring avian endogenous viruses (evs) are active in their inherited chromosomal location (2, 21). We were therefore interested in the relationship between provirus expression and the structure and activity of virus preintegration sites in this system.The avian endogenous viruses are highly related and stable genetic elements that were introduced into the germ line of chickens during evolution (1,7,24,25,33). Of the three viruses analyzed in this report, ev-1 and ev-2 are normally inactive in their inherited locations (producing less than 1 copy of stable RNA per cell; 2, 21), while ev-3 is active (producing 50 to 100 copies of stable mRNAs per cell; 2, 21...

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Section: Discussionmentioning

confidence: 70%

Varied interactions between proviruses and adjacent host chromatin.

Conklin¹,

Groudine²

1986

Mol. Cell. Biol.

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“…After severe anemia, erythrocyte pool is restored by 3 various differentiation pathways [1][2][3][4][5]7]. At the terminal stage of anemia, the reserve (emergency) pathway of erythropoiesis is manifested in transitory accumulation of basophilic erythroblasts (BE) in the bone marrow accompanied by a decrease in their mitotic activity [5,7].…”

Section: Abstract: Stress Erythropoiesis; Reserve Erythropoiesis; Ermentioning

confidence: 99%

“…At the terminal stage of anemia, the reserve (emergency) pathway of erythropoiesis is manifested in transitory accumulation of basophilic erythroblasts (BE) in the bone marrow accompanied by a decrease in their mitotic activity [5,7]. Some BE enter S phase of the cell cycle (duplication of DNA and cytoplasm), but do not enter mitosis and undergo rapid differentiation [7,8]. Hence, immature cells (primarily macrocytes in mammals) are recruited into the blood and maintain the function of various body systems until the formation of mature erythrocytes due to intense and accelerated erythroid differentiation.…”

Section: Abstract: Stress Erythropoiesis; Reserve Erythropoiesis; Ermentioning

confidence: 99%

Ability of peritoneal exudate cells to trigger various mechanisms of erythroid differentiation at different terms after massive blood loss in mice

Belan

2000

Bull Exp Biol Med

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Thirty minutes after massive blood loss, peritoneal cells gained the ability to trigger reparative erythropoiesis in the bone marrow of normal syngeneic recipients. This was manifested in proliferation of oxyphilic erythroblasts and activation of the reserve pathway of erythroid differentiation 4 days after cell transplantation. The maximum transfer capacity of peritoneal cells was observed 4 h after blood loss, but 4 days later they only initiated mitoses in oxyphilic erythroblasts.

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“…One of these routes, "reserve erythropoiesis," is an emergency route of accelerated differentiation of ceils providing for the survival of the organism during the early periods after massive blood loss. It consists in the omission of severn terminal stages and the rapid release of morphologically immature cells into the blood [2,3,[6][7][8]. A transito13" increase in the content of basophilic erythroblasts (BE) in the bone marrow paralleled by a decrease of their mitotic activity may be considered as a bone marrow marker of "reserve erythropoiesis" [3,7].…”

mentioning

confidence: 99%

“…It consists in the omission of severn terminal stages and the rapid release of morphologically immature cells into the blood [2,3,[6][7][8]. A transito13" increase in the content of basophilic erythroblasts (BE) in the bone marrow paralleled by a decrease of their mitotic activity may be considered as a bone marrow marker of "reserve erythropoiesis" [3,7]. Moreover, blood loss enhances polychromatophilic erythroblasts (PE) amplification and initiates mitoses in oxyphilic erythroblasts (OE), which normally almost never divide [1,3].…”

mentioning

confidence: 99%

The role of peritoneal T lymphocytes and macrophages in the initiation of stress erythropoiesisin vivo following a single massive blood loss in mice

Belan

Головкина

1994

Bull Exp Biol Med

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Peritoneal ceils of anemic donors enriched with macrophages at the expense of Tcell lysis using anti-Thy-1.2 monoclonal antibodies are capable of triggering various routes of terminal erythroid differentiation characteristic of stress erythropoiesis during their adoptive transfer to normal syngeneic recipients. Stimulation of the proliferation of polychromatophilic erythroblasts and initiation of mitoses in oxyphilic erythroblasts are regulated by interacting T ceUs and macrophages, and the "reserve erythropoiesis" mainly by macrophages. Key Words: stress erythropoiesis; peritoneal cells; reserve erythropoiesis; blood lossIn mammals with severe anemias the erythroid precursors, on reaching the terminal stages, form red ceils as a result of terminal differentiation by various routes. One of these routes, "reserve erythropoiesis," is an emergency route of accelerated differentiation of ceils providing for the survival of the organism during the early periods after massive blood loss. It consists in the omission of severn terminal stages and the rapid release of morphologically immature cells into the blood [2,3,[6][7][8]. A transito13" increase in the content of basophilic erythroblasts (BE) in the bone marrow paralleled by a decrease of their mitotic activity may be considered as a bone marrow marker of "reserve erythropoiesis" [3,7]. Moreover, blood loss enhances polychromatophilic erythroblasts (PE) amplification and initiates mitoses in oxyphilic erythroblasts (OE), which normally almost never divide [1,3].

show abstract

Genome Activity and Gene Expression in Avian Erythroid Cells

Cited by 14 publications

References 116 publications

Varied interactions between proviruses and adjacent host chromatin.

Varied interactions between proviruses and adjacent host chromatin.

Ability of peritoneal exudate cells to trigger various mechanisms of erythroid differentiation at different terms after massive blood loss in mice

The role of peritoneal T lymphocytes and macrophages in the initiation of stress erythropoiesisin vivo following a single massive blood loss in mice

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