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SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

Yan R, Thomas SE, Tsai JH, Yamada Y, McKee BD - J. Cell Biol. (2010)

Bottom Line: Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages.SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin.The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.

ABSTRACT
Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila. In solo mutants, sister centromeres separate before prometaphase I, disrupting meiosis I centromere orientation and causing nondisjunction of both homologous and sister chromatids. Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages. SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin. The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

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Molecular characterization of solo. (A) The genomic structure of solo and vas. The solo and vas transcription units share exons 1–3. Gray shading represents shared translated sequences, and white represents the 5′ and 3′ untranslated region. Exons 4’ and 5′ (blue) are unique to solo, and exons 4–8 (red) are unique to vas. Mutations above the locus are vas alleles, those in red fully complement solo, and those in black fail to complement solo. solo mutations are shown below the locus. (B) Predicted structures of SOLO and VASA proteins and mutation sites of solo alleles.
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fig5: Molecular characterization of solo. (A) The genomic structure of solo and vas. The solo and vas transcription units share exons 1–3. Gray shading represents shared translated sequences, and white represents the 5′ and 3′ untranslated region. Exons 4’ and 5′ (blue) are unique to solo, and exons 4–8 (red) are unique to vas. Mutations above the locus are vas alleles, those in red fully complement solo, and those in black fail to complement solo. solo mutations are shown below the locus. (B) Predicted structures of SOLO and VASA proteins and mutation sites of solo alleles.

Mentions: solo was mapped by deficiency complementation to the vasa (vas) locus at 35B on chromosome arm 2L (Fig. 5 A). vas encodes a conserved DEAD box RNA helicase involved in germline establishment and axis specification in oocytes and early embryos (Styhler et al., 1998; Tinker et al., 1998). Cohesion defects have not been previously described in vas mutants. Consistent with this, our DNA sequence analysis revealed no mutations in the vas coding sequences in any of the solo alleles. However, sequence alterations were found within the third intron of vas, which contains two large exons. Each of the three solo alleles exhibited a single-base substitution that creates a premature stop codon in one of those exons.


SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

Yan R, Thomas SE, Tsai JH, Yamada Y, McKee BD - J. Cell Biol. (2010)

Molecular characterization of solo. (A) The genomic structure of solo and vas. The solo and vas transcription units share exons 1–3. Gray shading represents shared translated sequences, and white represents the 5′ and 3′ untranslated region. Exons 4’ and 5′ (blue) are unique to solo, and exons 4–8 (red) are unique to vas. Mutations above the locus are vas alleles, those in red fully complement solo, and those in black fail to complement solo. solo mutations are shown below the locus. (B) Predicted structures of SOLO and VASA proteins and mutation sites of solo alleles.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2819681&req=5

fig5: Molecular characterization of solo. (A) The genomic structure of solo and vas. The solo and vas transcription units share exons 1–3. Gray shading represents shared translated sequences, and white represents the 5′ and 3′ untranslated region. Exons 4’ and 5′ (blue) are unique to solo, and exons 4–8 (red) are unique to vas. Mutations above the locus are vas alleles, those in red fully complement solo, and those in black fail to complement solo. solo mutations are shown below the locus. (B) Predicted structures of SOLO and VASA proteins and mutation sites of solo alleles.
Mentions: solo was mapped by deficiency complementation to the vasa (vas) locus at 35B on chromosome arm 2L (Fig. 5 A). vas encodes a conserved DEAD box RNA helicase involved in germline establishment and axis specification in oocytes and early embryos (Styhler et al., 1998; Tinker et al., 1998). Cohesion defects have not been previously described in vas mutants. Consistent with this, our DNA sequence analysis revealed no mutations in the vas coding sequences in any of the solo alleles. However, sequence alterations were found within the third intron of vas, which contains two large exons. Each of the three solo alleles exhibited a single-base substitution that creates a premature stop codon in one of those exons.

Bottom Line: Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages.SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin.The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.

ABSTRACT
Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila. In solo mutants, sister centromeres separate before prometaphase I, disrupting meiosis I centromere orientation and causing nondisjunction of both homologous and sister chromatids. Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages. SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin. The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

Show MeSH
Related in: MedlinePlus