Separable roles in vivo for the two RNA binding domains of a Drosophila A1-hnRNP homolog

Zu, Kai; Sikes, Martha L.; Beyer, Ann L.

doi:10.1017/s135583829898102x

Cited by 27 publications

(17 citation statements)

References 78 publications

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“…In the current model (Fig. 2), the binding of a subset of these hnRNPs to omega-n is likely to be dependent upon their high affinity for a short, but highly conserved motif AUAGGUAGG that occurs twice within each of the numerous omega-n repeats (Zu et al 1998). In this model the tandem repeats of omega-n serve to quantitatively bind specific hnRNPs, while those remaining unbound are available for nuclear processing of pre-mRNAs with ensuing transport of mature mRNAs to the cytoplasm for protein synthesis.…”

Section: Introductionmentioning

confidence: 89%

Protein synthesis rates in Drosophila associate with levels of the hsr-omega nuclear transcript

Johnson

Carrington

Hallas

et al. 2009

Cell Stress and Chaperones

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Transcripts of the Drosophila hsr-omega gene are known to interact with RNA processing factors and ribosomes and are postulated to aid in co-ordinating nuclear and cytoplasmic activities particularly in stressed cells. However, the significance of these interactions for physiological processes and in turn for whole-organism fitness remains an open question. Because hsr-omega's cellular expression characteristics suggest it may influence protein synthesis, and because both genotypic and expression variation of hsr-omega have been associated with thermotolerance, we characterised 30 lines for variation in the rates of protein synthesis, measured in ovarian tissues, both before and after a mild heat shock, and for basal levels of the two main hsr-omega transcripts, omega-n and omega-c. As expected, the mild heat shock reduced protein synthesis rates. Large variation occurred among lines in levels of omega-n which was negatively associated with rates of basal protein synthesis-a result that supports the model for the cellular function of omega-n. Furthermore, omega-n levels were associated with hsr-omega genotype of the line parents. Little variation occurred among lines for omega-c levels and no associations were detected with protein synthesis or genotype. Since protein synthesis is a fundamental process for growth and development, we characterised the lines for several life-history traits; however, no associations with protein synthesis, omega-n or omega-c levels were detected. Our results are consistent with the idea that natural variation in hsr-omega expression influence rates of protein synthesis in this species.

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Section: Introductionmentioning

confidence: 89%

Protein synthesis rates in Drosophila associate with levels of the hsr-omega nuclear transcript

Johnson

Carrington

Hallas

et al. 2009

Cell Stress and Chaperones

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“…One such highly conserved sequence, across at least 12 Drosophila species, is a nonamer motif (AUAG-GUAGG), two of which are imbedded in each 280 bp monomer of the repeats (Bardsley L and McKechnie SW, unpublished). Evidence suggests that these motifs, that are part of the nuclear transcript, may associate with heterogeneous ribonuclear proteins (hnRNPs) and help coordinate the availability of hnRNPs for messenger RNA processing (Zu et al, 1998). In relation to the latitudinal cline, populations at cooler latitudes on average have fewer repeating nonamers (shorter omegan transcripts) and therefore would have few binding sites to sequester hnRNPs with possible downstream affects on rates of messenger RNA processing and protein synthesis.…”

Section: Hsr-omega-l Chromosomesmentioning

confidence: 99%

Latitudinal and cold-tolerance variation associate with DNA repeat-number variation in the hsr-omega RNA gene of Drosophila melanogaster

et al. 2008

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“…pGST CAS YXXP, a gift from Amy Bouton, contains the YXXP domain of CAS in pGEX-2T-K (9). pBS-HRB87F contains a FLAG-tagged Drosophila Hrb87F gene in pBluescript II KS(ϩ) (65). The glutathione S-transferase (GST) fusion plasmids E1A ⌬2-36 , E1A ⌬38-67 , E1A ⌬73-120 , and the double point mutant E1A pm928/961 were gifts from Joseph R. Nevins (38).…”

Section: Cells and Virusesmentioning

confidence: 99%

Adenovirus Protein VII Condenses DNA, Represses Transcription, and Associates with Transcriptional Activator E1A

Johnson

Osheim

Xue

et al. 2004

J Virol

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Adenovirus protein VII is the major protein component of the viral nucleoprotein core. It is highly basic, and an estimated 1070 copies associate with each viral genome, forming a tightly condensed DNA-protein complex. We have investigated DNA condensation, transcriptional repression, and specific protein binding by protein VII. Xenopus oocytes were microinjected with mRNA encoding HA-tagged protein VII and prepared for visualization of lampbrush chromosomes. Immunostaining revealed that protein VII associated in a uniform manner across entire chromosomes. Furthermore, the chromosomes were significantly condensed and transcriptionally silenced, as judged by the dramatic disappearance of transcription loops characteristic of lampbrush chromosomes. During infection, the protein VII-DNA complex may be the initial substrate for transcriptional activation by cellular factors and the viral E1A protein. To investigate this possibility, mRNAs encoding E1A and protein VII were comicroinjected into Xenopus oocytes. Interestingly, whereas E1A did not associate with chromosomes in the absence of protein VII, expression of both proteins together resulted in significant association of E1A with lampbrush chromosomes. Binding studies with proteins produced in bacteria or human cells or by in vitro translation showed that E1A and protein VII can interact in vitro. Structure-function analysis revealed that an N-terminal region of E1A is responsible for binding to protein VII. These studies define the in vivo functions of protein VII in DNA binding, condensation, and transcriptional repression and indicate a role in E1A-mediated transcriptional activation of viral genes.The adenovirus nucleoprotein core consists of doublestranded genomic DNA, three highly basic viral proteins VII, V, and (mu), as well as protein IVa2 and the 55-kDa terminal protein (1,8,33,42,(52)(53)(54)61). Protein VII is the major protein component of the core, with an estimated 1,070 copies present per virion (20). Along with , it is bound noncovalently to the DNA in a sequence-independent manner (2, 6, 36, 55). Protein V contacts the DNA as well and also acts as a bridge between protein VII and the outer capsid (19,55). Protein IVa2 makes sequence-specific contacts with the viral DNA packaging sequence and is thought to play a role in DNA packaging (64). Salt-extracted preparations of the core contain only DNA and protein VII, suggesting that this protein is the most tightly DNA bound of all core proteins (60). Similarly, Sarkosyl preparations of the core contain predominantly DNA and protein VII (8).Structural features of the DNA-protein complex within the adenovirus capsid and during infection remain largely unknown. DNA within the capsid is in a highly compact configuration, and electron microscopy studies of purified viral core reveal structures reminiscent of beads on a string, or higherorder chromatin compaction, depending on the method of preparation (8,18,45,49,50,60,63). Nuclease digestion of core preparations results in discrete populations of prote...

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Separable roles in vivo for the two RNA binding domains of a Drosophila A1-hnRNP homolog

Cited by 27 publications

References 78 publications

Protein synthesis rates in Drosophila associate with levels of the hsr-omega nuclear transcript

Protein synthesis rates in Drosophila associate with levels of the hsr-omega nuclear transcript

Latitudinal and cold-tolerance variation associate with DNA repeat-number variation in the hsr-omega RNA gene of Drosophila melanogaster

Adenovirus Protein VII Condenses DNA, Represses Transcription, and Associates with Transcriptional Activator E1A

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