Limits...
mini spindles: A gene encoding a conserved microtubule-associated protein required for the integrity of the mitotic spindle in Drosophila.

Cullen CF, Deák P, Glover DM, Ohkura H - J. Cell Biol. (1999)

Bottom Line: Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells.The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast.In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cell and Molecular Biology, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom.

ABSTRACT
We describe a new Drosophila gene, mini spindles (msps) identified in a cytological screen for mitotic mutant. Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells. Nucleation of microtubules from centrosomes, metaphase alignment of chromosomes, or the focusing of spindle poles appears much less affected. The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast. Consistent with their sequence similarity, Msps protein also associates with microtubules in vitro. In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase. The absence of centrosomal staining in interphase of the cellularized embryos suggests that the interactions between Msps protein and microtubules or centrosomes may be regulated during the cell cycle.

Show MeSH

Related in: MedlinePlus

The Msps protein belongs to the dis1-TOG family. (a) Sequence comparison between Msps and human TOGp. Only identical residues are marked. Five putative cdc2 phosphorylation sites (S/TPXK/R) were identified in the COOH-terminal portion of the Msps protein (amino acids 1,564, 1,568, 1,803, 1,859, and 2,029). (b) Domain structure of members of the dis1-TOG family. From the top, human TOGp, D. melanogaster Msps, C. elegans ZYG-9, S. pombe Dis1, and S. cerevisiae STU2. Shaded boxes represent repeats (see c) common to all the dis1-TOG family. The COOH-terminal portions of the human and Drosophila proteins can be divided into two domains, one of which is also conserved in C. elegans protein, and the other found in Drosophila and vertebrates. (c) Amino acid sequences of the NH2-terminal repeats from the different proteins are aligned. Numbers in parentheses indicate the length of intervening amino acid sequences. The sequence of msps gene is available from GenBank/EMBL/DDBJ under accession number AJ249115.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2169485&req=5

Figure 4: The Msps protein belongs to the dis1-TOG family. (a) Sequence comparison between Msps and human TOGp. Only identical residues are marked. Five putative cdc2 phosphorylation sites (S/TPXK/R) were identified in the COOH-terminal portion of the Msps protein (amino acids 1,564, 1,568, 1,803, 1,859, and 2,029). (b) Domain structure of members of the dis1-TOG family. From the top, human TOGp, D. melanogaster Msps, C. elegans ZYG-9, S. pombe Dis1, and S. cerevisiae STU2. Shaded boxes represent repeats (see c) common to all the dis1-TOG family. The COOH-terminal portions of the human and Drosophila proteins can be divided into two domains, one of which is also conserved in C. elegans protein, and the other found in Drosophila and vertebrates. (c) Amino acid sequences of the NH2-terminal repeats from the different proteins are aligned. Numbers in parentheses indicate the length of intervening amino acid sequences. The sequence of msps gene is available from GenBank/EMBL/DDBJ under accession number AJ249115.

Mentions: The sequence of the msps gene predicts it to encode a protein of 2,050 amino acids, with an estimated molecular mass of 227 kD and an isoelectric point of 8.4. Database searches revealed that the entire region of the Msps protein has striking similarity to the human TOG protein (Charrasse et al. 1995, Charrasse et al. 1998; Fig. 4 a). Further analysis identified a family of proteins which share small regions of similarity. This family, which here we call the dis1-TOG family, consists of proteins encoded by Schizosaccharomyces pombe dis1 (Ohkura et al. 1988; Nabeshima et al. 1995), Saccharomyces cerevisiae STU2 (Wang and Huffaker, 1998), Caenorhabditis elegans zyg-9 (Wood et al. 1980; Mathews et al., 1998), Xenopus laevis XMAP215 (Gard and Kirschner 1987; Charrasse et al. 1998; the entire sequence not published), and human ch-TOG, all of which have been reported to have microtubule binding activity. The common signature among all members of the family is limited to four separate motifs within a repeated sequence unit (Fig. 4b and Fig. c). The repeats are each ∼200 amino acids long and tandemly arranged in the amino terminus with ∼100 residue spacers. Interestingly the two yeast proteins and the C. elegans ZYG-9 have only two repeats, while those from Drosophila and vertebrates have four.


mini spindles: A gene encoding a conserved microtubule-associated protein required for the integrity of the mitotic spindle in Drosophila.

Cullen CF, Deák P, Glover DM, Ohkura H - J. Cell Biol. (1999)

The Msps protein belongs to the dis1-TOG family. (a) Sequence comparison between Msps and human TOGp. Only identical residues are marked. Five putative cdc2 phosphorylation sites (S/TPXK/R) were identified in the COOH-terminal portion of the Msps protein (amino acids 1,564, 1,568, 1,803, 1,859, and 2,029). (b) Domain structure of members of the dis1-TOG family. From the top, human TOGp, D. melanogaster Msps, C. elegans ZYG-9, S. pombe Dis1, and S. cerevisiae STU2. Shaded boxes represent repeats (see c) common to all the dis1-TOG family. The COOH-terminal portions of the human and Drosophila proteins can be divided into two domains, one of which is also conserved in C. elegans protein, and the other found in Drosophila and vertebrates. (c) Amino acid sequences of the NH2-terminal repeats from the different proteins are aligned. Numbers in parentheses indicate the length of intervening amino acid sequences. The sequence of msps gene is available from GenBank/EMBL/DDBJ under accession number AJ249115.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169485&req=5

Figure 4: The Msps protein belongs to the dis1-TOG family. (a) Sequence comparison between Msps and human TOGp. Only identical residues are marked. Five putative cdc2 phosphorylation sites (S/TPXK/R) were identified in the COOH-terminal portion of the Msps protein (amino acids 1,564, 1,568, 1,803, 1,859, and 2,029). (b) Domain structure of members of the dis1-TOG family. From the top, human TOGp, D. melanogaster Msps, C. elegans ZYG-9, S. pombe Dis1, and S. cerevisiae STU2. Shaded boxes represent repeats (see c) common to all the dis1-TOG family. The COOH-terminal portions of the human and Drosophila proteins can be divided into two domains, one of which is also conserved in C. elegans protein, and the other found in Drosophila and vertebrates. (c) Amino acid sequences of the NH2-terminal repeats from the different proteins are aligned. Numbers in parentheses indicate the length of intervening amino acid sequences. The sequence of msps gene is available from GenBank/EMBL/DDBJ under accession number AJ249115.
Mentions: The sequence of the msps gene predicts it to encode a protein of 2,050 amino acids, with an estimated molecular mass of 227 kD and an isoelectric point of 8.4. Database searches revealed that the entire region of the Msps protein has striking similarity to the human TOG protein (Charrasse et al. 1995, Charrasse et al. 1998; Fig. 4 a). Further analysis identified a family of proteins which share small regions of similarity. This family, which here we call the dis1-TOG family, consists of proteins encoded by Schizosaccharomyces pombe dis1 (Ohkura et al. 1988; Nabeshima et al. 1995), Saccharomyces cerevisiae STU2 (Wang and Huffaker, 1998), Caenorhabditis elegans zyg-9 (Wood et al. 1980; Mathews et al., 1998), Xenopus laevis XMAP215 (Gard and Kirschner 1987; Charrasse et al. 1998; the entire sequence not published), and human ch-TOG, all of which have been reported to have microtubule binding activity. The common signature among all members of the family is limited to four separate motifs within a repeated sequence unit (Fig. 4b and Fig. c). The repeats are each ∼200 amino acids long and tandemly arranged in the amino terminus with ∼100 residue spacers. Interestingly the two yeast proteins and the C. elegans ZYG-9 have only two repeats, while those from Drosophila and vertebrates have four.

Bottom Line: Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells.The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast.In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cell and Molecular Biology, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom.

ABSTRACT
We describe a new Drosophila gene, mini spindles (msps) identified in a cytological screen for mitotic mutant. Mutation in msps disrupts the structural integrity of the mitotic spindle, resulting in the formation of one or more small additional spindles in diploid cells. Nucleation of microtubules from centrosomes, metaphase alignment of chromosomes, or the focusing of spindle poles appears much less affected. The msps gene encodes a 227-kD protein with high similarity to the vertebrate microtubule-associated proteins (MAPs), human TOGp and Xenopus XMAP215, and with limited similarity to the Dis1 and STU2 proteins from fission yeast and budding yeast. Consistent with their sequence similarity, Msps protein also associates with microtubules in vitro. In the embryonic division cycles, Msps protein localizes to centrosomal regions at all mitotic stages, and spreads over the spindles during metaphase and anaphase. The absence of centrosomal staining in interphase of the cellularized embryos suggests that the interactions between Msps protein and microtubules or centrosomes may be regulated during the cell cycle.

Show MeSH
Related in: MedlinePlus