scholarly journals Drosophila Histone Locus Body assembly and function involves multiple interactions

2020 ◽  
Author(s):  
Kaitlin P. Koreski ◽  
Leila E. Rieder ◽  
Lyndsey M. McLain ◽  
William F. Marzluff ◽  
Robert J. Duronio

AbstractThe histone locus body (HLB) assembles at replication-dependent (RD) histone loci and concentrates factors required for RD histone mRNA biosynthesis. The D. melanogaster genome has a single locus comprised of ∼100 copies of a tandemly arrayed repeat unit containing one copy of each of the 5 RD histone genes. To determine sequence elements required for D. melanogaster HLB formation and histone gene expression, we used transgenic gene arrays containing 12 copies of the histone repeat unit that functionally complement loss of the ∼200 endogenous RD histone genes. A 12x histone gene array in which all H3-H4 promoters were replaced with H2a-H2b promoters does not form an HLB or express high levels of RD histone mRNA in the presence of the endogenous histone genes. In contrast, this same transgenic array is active in HLB assembly and RD histone gene expression in the absence of the endogenous RD histone genes and rescues the lethality caused by homozygous deletion of the RD histone locus. The HLB formed in the absence of endogenous RD histone genes on the mutant 12x array contains all known factors present in the wild type HLB including CLAMP, which normally binds to GAGA repeats in the H3-H4 promoter. These data suggest that multiple protein-protein and/or protein-DNA interactions contribute to HLB formation, and that the large number of endogenous RD histone gene copies sequester available factor(s) from attenuated transgenic arrays, thereby preventing HLB formation and gene expression.

2021 ◽  
pp. mbc.E20-10-0645
Author(s):  
James P. Kemp ◽  
Xiao-Cui Yang ◽  
Zbigniew Dominski ◽  
William F. Marzluff ◽  
Robert J. Duronio

The Histone Locus Body (HLB) is an evolutionarily conserved nuclear body that regulates the transcription and processing of replication-dependent (RD) histone mRNAs, which are the only eukaryotic mRNAs lacking a poly-A tail. Many nuclear bodies contain distinct domains, but how internal organization is related to nuclear body function is not fully understood. Here, we demonstrate using structured illumination microscopy that Drosophila HLBs have a “core-shell” organization in which the internal core contains transcriptionally active RD histone genes. The N-terminus of Mxc, which contains a domain required for Mxc oligomerization, HLB assembly, and RD histone gene expression, is enriched in the HLB core. In contrast, the C-terminus of Mxc is enriched in the HLB outer shell as is FLASH, a component of the active U7 snRNP that co-transcriptionally cleaves RD histone pre-mRNA. Consistent with these results, we show biochemically that FLASH binds directly to the Mxc C-terminal region. In the rapid S-M nuclear cycles of syncytial blastoderm Drosophila embryos, the HLB disassembles at mitosis and reassembles the core-shell arrangement as histone gene transcription is activated immediately after mitosis. Thus, the core-shell organization is coupled to zygotic histone gene transcription, revealing a link between HLB internal organization and RD histone gene expression.


1984 ◽  
Vol 4 (7) ◽  
pp. 1363-1371 ◽  
Author(s):  
S J Flint ◽  
M A Plumb ◽  
U C Yang ◽  
G S Stein ◽  
J L Stein

The influence of adenovirus type 2 infection of HeLa cells upon expression of human histone genes was examined as a function of the period of infection. Histone RNA synthesis was assayed after run-off transcription in nuclei isolated from mock-infected cells and after various periods of adenovirus infection. Histone protein synthesis was measured by [3H]leucine labeling of intact cells and fluorography of electrophoretically fractionated nuclear and cytoplasmic proteins. The cellular representation of RNA species complementary to more than 13 different human histone genes was determined by RNA blot analysis of total cellular, nuclear or cytoplasmic RNA by using a series of 32P-labeled cloned human histone genes as hybridization probes and also by analysis of 3H-labeled histone mRNA species synthesized in intact cells. By 18 h after infection, HeLa cell DNA synthesis and all parameters of histone gene expression, including transcription and the nuclear and cytoplasmic concentrations of core and H1 mRNA species, were reduced to less than 5 to 10% of the control values. By contrast, transcription and processing of other cellular mRNA sequences have been shown to continue throughout this period of infection. The early period of adenovirus infection was marked by an inhibition of transcription of histone genes that accompanied the reduction in rate of HeLa cell DNA synthesis. These results suggest that the adenovirus-induced inhibition of histone gene expression is mediated in part at the transcriptional level. However, the persistence of histone mRNA species at concentrations comparable to those of mock-infected control cells during the early phase of the infection, despite a reduction in histone gene transcription and histone protein synthesis, implies that histone gene expression is also regulated post-transcriptionally in adenovirus-infected cells. These results suggest that the tight coupling between histone mRNA concentrations and the rate of cellular DNA synthesis, observed when DNA replication is inhibited by a variety of drugs, is not maintained after adenovirus infection.


1984 ◽  
Vol 4 (7) ◽  
pp. 1363-1371
Author(s):  
S J Flint ◽  
M A Plumb ◽  
U C Yang ◽  
G S Stein ◽  
J L Stein

The influence of adenovirus type 2 infection of HeLa cells upon expression of human histone genes was examined as a function of the period of infection. Histone RNA synthesis was assayed after run-off transcription in nuclei isolated from mock-infected cells and after various periods of adenovirus infection. Histone protein synthesis was measured by [3H]leucine labeling of intact cells and fluorography of electrophoretically fractionated nuclear and cytoplasmic proteins. The cellular representation of RNA species complementary to more than 13 different human histone genes was determined by RNA blot analysis of total cellular, nuclear or cytoplasmic RNA by using a series of 32P-labeled cloned human histone genes as hybridization probes and also by analysis of 3H-labeled histone mRNA species synthesized in intact cells. By 18 h after infection, HeLa cell DNA synthesis and all parameters of histone gene expression, including transcription and the nuclear and cytoplasmic concentrations of core and H1 mRNA species, were reduced to less than 5 to 10% of the control values. By contrast, transcription and processing of other cellular mRNA sequences have been shown to continue throughout this period of infection. The early period of adenovirus infection was marked by an inhibition of transcription of histone genes that accompanied the reduction in rate of HeLa cell DNA synthesis. These results suggest that the adenovirus-induced inhibition of histone gene expression is mediated in part at the transcriptional level. However, the persistence of histone mRNA species at concentrations comparable to those of mock-infected control cells during the early phase of the infection, despite a reduction in histone gene transcription and histone protein synthesis, implies that histone gene expression is also regulated post-transcriptionally in adenovirus-infected cells. These results suggest that the tight coupling between histone mRNA concentrations and the rate of cellular DNA synthesis, observed when DNA replication is inhibited by a variety of drugs, is not maintained after adenovirus infection.


1981 ◽  
Vol 1 (7) ◽  
pp. 661-671 ◽  
Author(s):  
A Mauron ◽  
S Levy ◽  
G Childs ◽  
L Kedes

We have examined histone gene expression during the early stages of sea urchin embryogenesis. The five histone genes expressed at that time are contained in tandem repetitive segments. It has been suggested that adjacent coding regions and their intervening spacer sequences are transcribed into large polycistronic messenger ribonucleic acid (RNA) precursors. We have subcloned into pBR322 deoxyribonucleic acid (DNA) sequences mapping either in the coding region, the 5' spacer, or the 3' spacer of the H2B histone gene. These clones were used to produce radioiodinated hybridization probes. We measured the steady-state quantity of H2B messenger RNA as well as spacer-specific RNA in the total RNA from embryos taken at various stages of development from fertilization to hatching of blastulae (0 to 22 h post-fertilization). Small amounts of RNA hybridizing to both spacer probes could be found. However, we show that these RNAs form mismatched hybrids with the spacer DNA and therefore cannot originate from the spacers present in the histone genes. We conclude that there is no detectable transcription of the spacer regions on either side of the H2B histone gene. The detection limit for RNA complementary to the 5' spacer sequence corresponds to a maximum of about three RNA molecules per cell, an amount shown to be far less than the projected steady-state pool size of a putative polycistronic transcript, if such a precursor were to be the obligatory transcript of the histone genes. (This conclusion was derived by using the known rates of production of H2B mRNA throughout early development [R. E. Maxson and F. H. Wilt, Dev. Biol., in press].) The physiologically relevant transcript of the histone genes in early development is therefore monocistronic and probably identical to the messenger RNA itself.


1982 ◽  
Vol 79 (3) ◽  
pp. 749-753 ◽  
Author(s):  
R. Rickles ◽  
F. Marashi ◽  
F. Sierra ◽  
S. Clark ◽  
J. Wells ◽  
...  

2020 ◽  
Vol 31 (14) ◽  
pp. 1525-1537
Author(s):  
Kaitlin P. Koreski ◽  
Leila E. Rieder ◽  
Lyndsey M. McLain ◽  
Ashlesha Chaubal ◽  
William F. Marzluff ◽  
...  

By using a histone gene replacement platform in Drosophila, we show that interactions among multiple factors contribute to HLB formation, and that the large number of genes at the endogenous histone locus sequesters available factors from attenuated transgenic histone gene arrays, thereby preventing HLB formation and histone gene expression from these arrays.


2007 ◽  
Vol 35 (5) ◽  
pp. 1369-1371 ◽  
Author(s):  
B. Müller ◽  
J. Blackburn ◽  
C. Feijoo ◽  
X. Zhao ◽  
C. Smythe

In metazoans, accurate replication of chromosomes is ensured by the coupling of DNA synthesis to the synthesis of histone proteins. Expression of replication-dependent histone genes is restricted to S-phase by a combination of cell cycle-regulated transcriptional and post-transcriptional control mechanisms and is linked to DNA replication by a poorly understood mechanism involving checkpoint kinases [Su, Gao, Schneider, Helt, Weiss, O'Reilly, Bohmann and Zhao (2004) EMBO J. 23, 1133–1143; Kaygun and Marzluff (2005) Nat. Struct. Mol. Biol. 12, 794–800]. Here we propose a model for the molecular mechanisms that link these two important processes within S-phase, and propose roles for multiple checkpoints in this mechanism.


1981 ◽  
Vol 1 (7) ◽  
pp. 661-671
Author(s):  
A Mauron ◽  
S Levy ◽  
G Childs ◽  
L Kedes

We have examined histone gene expression during the early stages of sea urchin embryogenesis. The five histone genes expressed at that time are contained in tandem repetitive segments. It has been suggested that adjacent coding regions and their intervening spacer sequences are transcribed into large polycistronic messenger ribonucleic acid (RNA) precursors. We have subcloned into pBR322 deoxyribonucleic acid (DNA) sequences mapping either in the coding region, the 5' spacer, or the 3' spacer of the H2B histone gene. These clones were used to produce radioiodinated hybridization probes. We measured the steady-state quantity of H2B messenger RNA as well as spacer-specific RNA in the total RNA from embryos taken at various stages of development from fertilization to hatching of blastulae (0 to 22 h post-fertilization). Small amounts of RNA hybridizing to both spacer probes could be found. However, we show that these RNAs form mismatched hybrids with the spacer DNA and therefore cannot originate from the spacers present in the histone genes. We conclude that there is no detectable transcription of the spacer regions on either side of the H2B histone gene. The detection limit for RNA complementary to the 5' spacer sequence corresponds to a maximum of about three RNA molecules per cell, an amount shown to be far less than the projected steady-state pool size of a putative polycistronic transcript, if such a precursor were to be the obligatory transcript of the histone genes. (This conclusion was derived by using the known rates of production of H2B mRNA throughout early development [R. E. Maxson and F. H. Wilt, Dev. Biol., in press].) The physiologically relevant transcript of the histone genes in early development is therefore monocistronic and probably identical to the messenger RNA itself.


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