An unusual split Drosophila heat shock gene expressed during embryogenesis, pupation and in testis

Pauli, Daniel; Tonka, Chia-Hwa; Ayme-Southgate, Agnes

doi:10.1016/0022-2836(88)90332-4

Cited by 39 publications

(20 citation statements)

References 55 publications

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“…In the experiments shown in Supplemental Figure S1, we studied several proteins, which were reported to be located in other cellular compartments in some studies: Erg9 and Erg6 that are involved in sterol synthesis, a member of the Rho family (Rho1), Pho88, and the alcohol acyl transferase Eht1 (Leber et al, 1998;Kumar et al, 2002;Huh et al, 2003). We also included two proteins of unknown function and localization: Yor285w, a conserved protein with high homology to the Drosophila melanogaster heat-shock protein 67B2 (Pauli et al, 1988), and Hfd1 (Ymr110c; see below). Localization in the mitochondrial outer membrane was analyzed by different means.…”

Section: Identification Of Proteins In Purified Mitochondrial Outer Mmentioning

confidence: 99%

Proteomic Analysis of the Yeast Mitochondrial Outer Membrane Reveals Accumulation of a Subclass of Preproteins

Zahedi

Sickmann

Boehm

et al. 2006

MBoC

201

180

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Mitochondria consist of four compartments-outer membrane, intermembrane space, inner membrane, and matrix-with crucial but distinct functions for numerous cellular processes. A comprehensive characterization of the proteome of an individual mitochondrial compartment has not been reported so far. We used a eukaryotic model organism, the yeast Saccharomyces cerevisiae, to determine the proteome of highly purified mitochondrial outer membranes. We obtained a coverage of ϳ85% based on the known outer membrane proteins. The proteome represents a rich source for the analysis of new functions of the outer membrane, including the yeast homologue (Hfd1/Ymr110c) of the human protein causing Sjö gren-Larsson syndrome. Surprisingly, a subclass of proteins known to reside in internal mitochondrial compartments were found in the outer membrane proteome. These seemingly mislocalized proteins included most top scorers of a recent genome-wide analysis for mRNAs that were targeted to mitochondria and coded for proteins of prokaryotic origin. Together with the enrichment of the precursor form of a matrix protein in the outer membrane, we conclude that the mitochondrial outer membrane not only contains resident proteins but also accumulates a conserved subclass of preproteins destined for internal mitochondrial compartments.

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Section: Identification Of Proteins In Purified Mitochondrial Outer Mmentioning

confidence: 99%

Proteomic Analysis of the Yeast Mitochondrial Outer Membrane Reveals Accumulation of a Subclass of Preproteins

Zahedi

Sickmann

Boehm

et al. 2006

MBoC

201

180

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“…Whether or not this expression is driven by internal damages that accumulate during aging remains to be determined. The expression of the sHsps has been determined either by immunological methods involving the use of antibodies recognizing specific members of the sHsp family [57,[61][62][63] or by promoter-driven reporter gene expression in transgenic flies [47,64]. Hsp23 is expressed during embryogenesis in specific glial cells, tentatively identified as midline glial cells [6,61,65].…”

Section: Hsps Show a Stage-and Cell-specific Pattern Of Expression Inmentioning

confidence: 99%

Regulation of heat shock gene induction and expression during Drosophila development

Michaud¹,

Marín²,

Tanguay³

1997

CMLS, Cell. mol. life sci.

110

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Some heat shock genes are expressed in the absence of stress during embryogenesis and metamorphosis in the fruit fly Drosophila melanogaster. Their functions in these processes are unknown. During development, each of the four members of the small heat shock protein family (Hsp27, Hsp26 Hsp23 and Hsp22), which are coordinately induced in response to a heat stress, shows a specific pattern of expression in diverse tissues and cells. This expression is driven through cell-specific enhancers in the promoter regions of their genes. In addition, some of the Hsps show cell-specific induction by heat shock. Hsp23, for example, is only inducible in a single cell type (cone cells) of the eye ommatidium, while the other small Hsps are inducible in all cells of the eye unit. In germ line tissues such as testes, Hsp23 and 27 are both readily expressed in the absence of stress (albeit in distinct cell lineages) and cannot be further induced by heat shock. Hsp27 is expressed throughout oogenesis, but its intracellular localization is stage-specific, being nuclear from germarium to stage 6 and cytoplasmic from stage 8 onwards. Finally the small Hsps show tissue-specific post-translational modifications. Thus the function(s) of the small Hsps may be modulated by different cell and developmental stage-specific mechanisms operating either on their expression, their cellular localization or their structure by post-translational modifications.

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“…Second, after heat shock some heat-inducible transcripts are found to extend far beyond the usual polyadenylation site. Examples include gene 2 (63) and certain small hsp gene transcripts (10) in D.…”

mentioning

confidence: 99%

Preferential deadenylation of Hsp70 mRNA plays a key role in regulating Hsp70 expression in Drosophila melanogaster.

1994

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Following a standard heat shock, -40%o ofHsp7O transcripts in Drosophila melanogaster lack a poly(A) tail. Since heat shock disrupts other aspects of RNA processing, this observation suggested that heat might disrupt polyadenylation as well. We find, however, that as the temperature is increased a larger fraction of Hsp7O RNA is polyadenylated. Poly(A)-deficient Hsp7O RNAs arise not from a failure in polyadenylation but from the rapid and selective removal of poly(A) from previously adenylated transcripts. Poly(A) removal is highly regulated: poly(A) is (i) removed much more rapidly from Hsp7O RNAs than from Hsp23 RNAs, (ii) removed more rapidly after mild heat shocks than after severe heat shocks, and (iii) removed more rapidly after a severe heat shock if cells have first been conditioned by a mild heat treatment. Poly(A) seems to be removed by simple deadenylation rather than by endonucleolytic cleavage 5' of the adenylation site. During recovery from heat shock, deadenylation is rapidly followed by degradation. In cells maintained at high temperatures, however, the two processes are uncoupled and Hsp7O RNAs are deadenylated without being degraded. These deadenylated mRNAs are translated with low efficiency. Deadenylation therefore allows Hsp7O synthesis to be repressed even when degradation of the mRNA is blocked. Poly(A) tail shortening appears to play a key role in regulating Hsp7O expression.The most abundant and tightly regulated heat-inducible protein in Drosophila melanogaster is Hsp7O (47,62). Hsp7O and its relatives make up a highly conserved protein family, with eukaryotic, eubacterial, and archaebacterial members sharing at least 50% amino acid identity (27,30,47). Eukaryotes have several Hsp7O proteins. Some are constitutive and are required for normal growth, whereas others are heat inducible and help organisms cope with the toxic effects of heat. In D. melanogaster the haploid genome encodes five virtually identical heat-inducible Hsp7O proteins (32), which share -70 to 80% amino acid identity with their constitutively expressed relatives (61, 64). Consistent with their independent patterns of regulation, the 3' and 5' sequences of the constitutive genes share little or no homology with those of the heat-inducible genes.The heat- strategies are used. First, the absence of introns in the Hsp7O gene (31) allows its transcripts to circumvent the high-temperature-induced block in mRNA splicing and move rapidly into the cytoplasm (91). Second, high temperatures block the turnover of the normally short-lived Hsp7O mRNA, allowing it to accumulate very rapidly to high concentrations (67). Third, the translation of normal cellular mRNAs is inhibited at high temperatures by mechanisms that act at the levels of both initiation and elongation (8,33,45,80). Hsp7O mRNAs are translated efficiently under these conditions because special sequences in their 5' untranslated leaders allow them to circumvent the block in translation (51; for a review, see reference 46).After return to normal temperatures, hsp synthe...

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An unusual split Drosophila heat shock gene expressed during embryogenesis, pupation and in testis

Cited by 39 publications

References 55 publications

Proteomic Analysis of the Yeast Mitochondrial Outer Membrane Reveals Accumulation of a Subclass of Preproteins

Proteomic Analysis of the Yeast Mitochondrial Outer Membrane Reveals Accumulation of a Subclass of Preproteins

Regulation of heat shock gene induction and expression during Drosophila development

Preferential deadenylation of Hsp70 mRNA plays a key role in regulating Hsp70 expression in Drosophila melanogaster.

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