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A novel kinesin-like protein with a calmodulin-binding domain 总被引:4,自引:0,他引:4
W. Wang D. Takezawa S. B. Narasimhulu A. S. N. Reddy B. W. Poovaiah 《Plant molecular biology》1996,31(1):87-100
Calcium regulates diverse developmental processes in plants through the action of calmodulin. A cDNA expression library from developing anthers of tobacco was screened with 35S-labeled calmodulin to isolate cDNAs encoding calmodulin-binding proteins. Among several clones isolated, a kinesin-like gene (TCK1) that encodes a calmodulin-binding kinesin-like protein was obtained. The TCK1 cDNA encodes a protein with 1265 amino acid residues. Its structural features are very similar to those of known kinesin heavy chains and kinesin-like proteins from plants and animals, with one distinct exception. Unlike other known kinesin-like proteins, TCK1 contains a calmodulin-binding domain which distinguishes it from all other known kinesin genes. Escherichia coli-expressed TCK1 binds calmodulin in a Ca2+-dependent manner. In addition to the presence of a calmodulin-binding domain at the carboxyl terminal, it also has a leucine zipper motif in the stalk region. The amino acid sequence at the carboxyl terminal of TCK1 has striking homology with the mechanochemical motor domain of kinesins. The motor domain has ATPase activity that is stimulated by microtubules. Southern blot analysis revealed that TCK1 is coded by a single gene. Expression studies indicated that TCK1 is expressed in all of the tissues tested. Its expression is highest in the stigma and anther, especially during the early stages of anther development. Our results suggest that Ca2+/calmodulin may play an important role in the function of this microtubule-associated motor protein and may be involved in the regulation of microtubule-based intracellular transport. 相似文献
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Previous studies identified a group of proteins localized to the endoplasmic reticulum (ER) that bind calcium and direct protein folding. Three of these proteins, CaBP1, CaBP2, and protein disulfide isomerase, have been purified from rat microsomes and analyzed biochemically. However, their function in vivo has not been determined. Here, we report the isolation of a homologue of the CaBP1 gene from the fruitfly Drosophila melanogaster (DmCaBP1). The predicted sequence of the Drosophila protein is very similar to that of rat CaBP1 and retains motifs thought to be functionally important in the mammalian protein. We show that DmCaBP1 is expressed in a specific spatiotemporal pattern during embryogenesis. In particular, it is expressed in midline precursor cells in the developing CNS. This is the first demonstration of tissue-specific expression for a member of this group of ER proteins and suggests a possible role for DmCABP1 as a molecular chaperone involved in nervous system development. The identification of the DmCaBP1 gene provides a basis for future genetic studies of its function. Dev. Genet. 23:104–110, 1998. © 1998 Wiley-Liss, Inc. 相似文献
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Shoichi Kawakami Kanae Mitsunaga Yara Yukie Kikuti Asako Ando Hidetoshi Inoko Ken-ichi Yamamura Kuniya Abe 《Mammalian genome》1998,9(11):874-880
Tctex3 showing restricted expression in male germ cells has been isolated during the process of chromosome walking in the mouse
t-complex region. The total sequence of Tctex3 cDNA predicts a protein of 580 amino acids with two C4HC3 type PHD fingers. The region containing this conserved motif is
shared among members of the Polycomblike proteins that include the mouse M96 and Drosophila Polycomblike. A partial cDNA for a human homolog of Tctex3, HUTEX3, has also been isolated. Mouse Tctex3 gene was mapped adjacent to Tsc2 gene on mouse Chromosome (Chr) 17, and HUTEX3 was located closely to HSET gene in the HLA class II region of chromosome 6.
Received: 10 April 1998 / Accepted: 22 June 1998 相似文献
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Joydeep Basu Elsa Logarinho Siegrun Herrmann Hassan Bousbaa ZeXiao Li Gordon K. T. Chan Tim J. Yen Claudio E. Sunkel Michael L. Goldberg 《Chromosoma》1998,107(6-7):376-385
We report here the isolation and molecular characterization of the Drosophila homolog of the mitotic checkpoint control protein Bub3. The Drosophila Bub3 protein is associated with the centromere/kinetochore of chromosomes in larval neuroblasts whose spindle assembly checkpoints
have been activated by incubation with the microtubule-depolymerizing agent colchicine. Drosophila Bub3 is also found at the kinetochore regions in mitotic larval neuroblasts and in meiotic primary and secondary spermatocytes,
with the strong signal seen during prophase and prometaphase becoming increasingly weaker after the chromosomes have aligned
at the metaphase plate. We further show that the localization of Bub3 to the kinetochore is disrupted by mutations in the
gene encoding the Drosophila homolog of the spindle assembly checkpoint protein Bub1. Combined with recent findings showing that the kinetochore localization
of Bub1 conversely depends upon Bub3, these results support the hypothesis that the spindle assembly checkpoint proteins exist
as a multiprotein complex recruited as a unit to the kinetochore. In contrast, we demonstrate that the kinetochore constituents
Zw10 and Rod are not needed for the binding of Bub3 to the kinetochore. This suggests that the kinetochore is assembled in
at least two relatively independent pathways.
Received: 6 August 1998 / Accepted: 28 August 1998 相似文献
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Human copper transporter Ctr1 is functional in Drosophila, revealing a high degree of conservation between mammals and insects 总被引:1,自引:0,他引:1
Haiqing Hua Oleg Georgiev Walter Schaffner Dominik Steiger 《Journal of biological inorganic chemistry》2010,15(1):107-113
Living cells have to carefully control the intracellular concentration of trace metals, especially of copper, which is at
the same time essential but owing to its redox activity can also facilitate generation of reactive oxygen species. Mammals
have two related copper transporters, Ctr1 and Ctr2, with Ctr1 playing the major role. The fruit fly Drosophila has three family members, termed Ctr1A, Ctr1B, and Ctr1C. Ctr1A is expressed throughout development, and a null mutation
causes lethality at an early stage. Ctr1B ensures efficient copper uptake in the intestinal tract, whereas Ctr1C is mainly
expressed in male gonads. Ectopic expression of Ctr1 transporters in Drosophila causes toxic effects due to excessive copper uptake. Here, we compare the effects of human Ctr1 (hCtr1) with those of the
Drosophila homologs Ctr1A and Ctr1B in two overexpression assays. Whereas the overexpression of Drosophila Ctr1A and Ctr1B results in strong phenotypes, expression of hCtr1 causes only a very mild phenotype, indicating a low copper-import
efficiency in the Drosophila system. However, this can be boosted by coexpressing the human copper chaperone CCS. Surprisingly, hCtr1 complements a lethal
Ctr1A mutation at least as well as Ctr1A and Ctr1B transgenes. These findings reveal a high level of conservation between
the mammalian and insect Ctr1-type copper importers, and they also demonstrate that the Drosophila Ctr1 proteins are functionally interchangeable. 相似文献
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L. Cheng N. Roemer K.-A. Smyth J. Belote J. R. Nambu L. M. Schwartz 《Molecular & general genetics : MGG》1998,259(1):13-20
The proteasome plays essential roles in a variety of cellular processes, including degradation of the bulk of cellular proteins,
degradation of short-lived proteins such as cell cycle regulators, generation of antigenic peptides, and mediating programmed
cell death. One of the best characterized subunits of the 26S proteasome is encoded by the yeast gene SUG1. We report here the cloning and characterization of the Drosophila homolog of this gene, Pros45. At the protein level, Pros45 is highly conserved with respect to its homologs in a variety of taxa: it shows 74% identity to yeast Sug1; 86% to mouse
m56/mSug1/FZA-B; 87% to human Trip1; and 97% to moth 18-56. Using a genomic clone as a probe for in situ hyridization to polytene
chromesomes, we demonstrated that Pros45 maps to 19F, near the base of the X chromosome. Use of a pros45 cDNA clone as a probe revealed a second site of hybridization at 99CD. Pros45 mRNA is found in the unfertilized egg and in all cells of the early embryo. By the end of embryogenesis, Pros45 is expressed predominantly in the central nervous system. Targeted expression of Pros45 in a variety of different cells using the Gal4 UAS P-element system failed to generate an overt phenotype. This study provides
the foundation for further examination of the role of the 26S proteasome in homeostasis and development in Drosophila.
Received: 23 October 1997 / Accepted: 6 March 1998 相似文献
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The embryonic expression pattern of labial, posterior homeotic complex genes and the teashirt homologue in an apterygote insect 总被引:1,自引:1,他引:0
During embryogenesis of the fruit fly, Drosophila melanogaster, the homeotic genes are required to specify proper cell fates along the anterior-posterior axis of the embryo. We cloned
partial cDNAs of homologues of the Drosophila homeotic gene teashirt and five of the homeotic-complex (HOM-C) genes from the thysanuran insect, Thermobia domestica, and assayed their embryonic expression patterns. The HOM-C genes we examined were labial, Antennapedia, Ultrabithorax, abdominal-A and Abdominal-B. As the expression pattern of these HOM-C genes is largely conserved among insects and as Thermobia is a member of a phylogenetically basal order of insects, we were able to infer their ancestral expression patterns in insects.
We compare the expression patterns of the Thermobia HOM-C genes with their expression in Drosophila and other insects and discuss the potential roles these genes may have played in insect evolution. Interestingly, the teashirt homologue shows greater variability between Thermobia and Drosophila than any of the HOM-C genes. In particular, teashirt is not expressed strongly in the Thermobia abdomen, unlike Drosophila teashirt. We propose that teashirt expression has expanded posteriorly in Drosophila and contributed to a homogenization of the Drosophila larval thorax and abdomen.
Received: 23 July 1998 / Accepted: 1 November 1998 相似文献
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Luke Alphey Louise Parker Gillian Hawcroft Yiquan Guo Kim Kaiser Gareth Morgan 《The Journal of cell biology》1997,138(2):395-409
We have identified a new member of the kinesin superfamily in Drosophila, KLP38B (kinesin-like protein at 38B). KLP38B was isolated through its two-hybrid interaction with the catalytic subunit of type 1 serine/threonine phosphoprotein phosphatase (PP1). We demonstrate that recombinant KLP38B and PP1 associate in vitro. This is the first demonstration of direct binding of a kinesin-related protein to a regulatory enzyme.
Though most closely related to the Unc-104 subfamily of kinesin-related proteins, KLP38B is expressed only in proliferating cells. KLP38B mutants show cell proliferation defects in many tissues. KLP38B is required for normal chromatin condensation as embryos from KLP38B mutant mothers have undercondensed chromatin at metaphase and anaphase. This is the first time that a kinesin-related protein has been shown to have such a role. Incomplete lethality of a strong KLP38B allele suggests partial redundancy with one or more additional kinesin-related proteins.
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To obtain a clearer understanding of the evolutionary transition between short- and long-germ modes of embryogenesis in insects,
we studied the expression of two gap genes hunchback (hb) and Krüppel (Kr) as well as the pair-rule gene even-skipped (eve) in the dipteran Clogmia albipunctata (Nematocera, Psychodidae). This species has features of both short- and long-germ mode of embryogenesis. In Clogmia
hb expression deviates from that known in Drosophila in two main respects: (1) it shows an extended dorsal domain that is linked to the large serosa anlage, and (2) it shows
a terminal expression in the proctodeal region. These expression patterns are reminiscent of the hb expression pattern in the beetle Tribolium, which has a short germ mode of embryogenesis. Krüppel expression, on the other hand, was found to be rather similar to the Drosophila expression, both at early and late stages. eve expression starts with six stripes formed at blastoderm stage, while the seventh is only formed after the onset of gastrulation
and germband extension. Surprisingly, no segmental secondary Eve stripes could be observed in Clogmia although such segmental stripes are known from higher dipterans, beetles and hymenopterans. We therefore also studied another
nematoceran, Coboldia, to address this question and found that some segmental stripes form by intercalation as in Drosophila, although belatedly. Our results suggest that Clogmia embryogenesis, both with respect to morphological and molecular characteristics represents an intermediate between the long-germ
mode known from higher dipterans such as Drosophila, and the short-germ mode found in more ancestral insects.
Received: 24 August 1998 / Accepted: 29 October 1998 相似文献
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Midkine (MK) and Pleiotrophin (PTN) are small heparin-binding cytokines with closely related structures. To date, this family
of proteins has been implicated in multiple processes, such as growth, survival, and migration of various cells, and has roles
in neurogenesis and epithelial–mesenchymal interaction during organogenesis. In this report, we have characterized two members
of the MK/PTN family of proteins in Drosophila, named Miple1 and Miple2, from Midkine and Pleiotrophin. Drosophila miple1 and miple2 encode secreted proteins which are expressed in spatially restricted, nonoverlapping patterns during embryogenesis. Expression
of miple1 can be found at high levels in the central nervous system, while miple2 is strongly expressed in the developing midgut endoderm. The identification of homologues of the MK/PTN family in this genetically
tractable model organism should allow an analysis of their function during complex developmental processes.
C. Englund, A. Birve, and L. Falileeva contributed equally to this work. 相似文献
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Distinct structural domains in the planarian brain defined by the expression of evolutionarily conserved homeobox genes 总被引:4,自引:4,他引:0
Homeobox genes such as orthodenticle in Drosophila and its mouse homologues, Otx1 and Otx2, are known to be essential for rostral brain development. To investigate the molecular basis of brain evolution, we searched
for otd/Otx-related homeobox genes in the planarian Dugesia japonica, and identified two genes, DjotxA and B, whose expression appears to be restricted to the cephalic ganglion (brain). DjotxA was expressed more medially, in the region containing the termini of the visual axons, and in the visual cells, suggesting
involvement in establishment of the visual system. DjotxB was expressed in a discrete region just lateral to the DjotxA-positive domain, but not in the more lateral branch structures, which in turn are characterized by the expression of Djotp, a planarian homeobox gene related to mouse Orthopedia (Otp). In transverse sections of planarians, DjotxA and B expression were observed only at the anterior ends of the stumps, corresponding to the regional pattern of the regenerating
brain. Our findings suggest that the planarian brain is composed of structurally distinct and functionally diverse domains
which are defined by the discrete expression of the three evolutionarily conserved homeobox genes.
Received: 17 June 1998 / Accepted: 20 August 1998 相似文献
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Caggese C Ragone G Perrini B Moschetti R De Pinto V Caizzi R Barsanti P 《Molecular & general genetics : MGG》1999,261(1):64-70
As a first step towards using cross-species comparison to complete the inventory of the nuclear genes that encode mitochondrial
polypeptides, and ultimately to understand their function through systematic molecular and genetic analysis in a model organism
of choice, we report here the characterization of 41 Drosophila melanogaster cDNAs. These cDNAs were isolated by screening an ovarian expression library with antibodies against mitochondrial proteins
and identify 17 novel Drosophila genes. The deduced amino acid sequences encoded by the majority of these cDNAs turned out to show significant homology to
mitochondrial proteins previously identified in other species. Among others, ORFs putatively encoding six different subunits
of ATP synthase and three NADH:ubiquinone reductase subunits were detected. By in situ hybridization, all cDNAs were mapped
to single bands on polytene chromosomes, thus identifying candidate Drosophila genes required for mitochondrial biogenesis and maintenance. A search of the Human Gene Index database made it possible in
most cases to align the entire Drosophila coding sequence with a human consensus sequence, suggesting that the cDNAs originate from insect counterparts of expressed
mammalian genes. Our experimental strategy represents an efficient approach to the identification and interspecies comparison
of genes encoding products targeted to the mitochondrion.
Received: 13 July 1998 / Accepted: 12 October 1998 相似文献