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PATRONUS1 is expressed in meiotic prophase I to regulate centromeric cohesion in Arabidopsis and shows synthetic lethality with OSD1.

Singh DK, Spillane C, Siddiqi I - BMC Plant Biol. (2015)

Bottom Line: Retention of sister centromere cohesion during meiosis I and its dissolution at meiosis II is necessary for balanced chromosome segregation and reduction of chromosome number.We show here that PANS1 protein is found mainly in prophase I of meiosis, with its level declining late in prophase I during diplotene.PANS1 also shows expression in dividing tissues.

View Article: PubMed Central - PubMed

Affiliation: Centre for Cellular and Molecular Biology (CSIR), Uppal Road, Hyderabad, 500007, India. dipesh@ccmb.res.in.

ABSTRACT

Background: Retention of sister centromere cohesion during meiosis I and its dissolution at meiosis II is necessary for balanced chromosome segregation and reduction of chromosome number. PATRONUS1 (PANS1) has recently been proposed to regulate centromere cohesion in Arabidopsis after meiosis I, during interkinesis. pans1 mutants lose centromere cohesion prematurely during interkinesis and segregate randomly at meiosis II. PANS1 protein interacts with components of the Anaphase Promoting Complex/Cyclosome (APC/C).

Results: We show here that PANS1 protein is found mainly in prophase I of meiosis, with its level declining late in prophase I during diplotene. PANS1 also shows expression in dividing tissues. We demonstrate that, in addition to the previously reported premature loss of centromere cohesion during interkinesis, pans1 mutants show partially penetrant defects in centromere cohesion during meiosis I. We also determine that pans1 shows synthetic lethality at the level of the sporophyte, with Omission of Second Division 1 (osd1), which encodes a known inhibitor of the APC/C that is required for cell cycle progression during mitosis, as well as meiosis I and II.

Conclusions: Our results show that PANS1 is expressed mainly in meiosis I where it has an important function and together with previous studies indicate that PANS1 and OSD1 are part of a network linking centromere cohesion and cell cycle progression through control of APC/C activity.

No MeSH data available.


Related in: MedlinePlus

Early loss of centromere cohesion in pans1 during meiosis II. Acid spreads of male meiotic chromosomes stained with DAPI. a-d wild type, e-ipans1. a,e Normal metaphase I. b, f Normal anaphase I. c Normal metaphase II d Normal anaphase II. g Early loss of cohesion in pans1 meiosis II prior to metaphase II. h Random movement of chromosomes in meiosis II in pans1. ipans1 defective metaphase I showing bipolar attachment (arrowheads) and univalents (*) in a subset of chromosomes
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Fig1: Early loss of centromere cohesion in pans1 during meiosis II. Acid spreads of male meiotic chromosomes stained with DAPI. a-d wild type, e-ipans1. a,e Normal metaphase I. b, f Normal anaphase I. c Normal metaphase II d Normal anaphase II. g Early loss of cohesion in pans1 meiosis II prior to metaphase II. h Random movement of chromosomes in meiosis II in pans1. ipans1 defective metaphase I showing bipolar attachment (arrowheads) and univalents (*) in a subset of chromosomes

Mentions: pans1 mutants of Arabidopsis have been recently reported to cause reduced fertility that arises from a defect in maintenance of centromeric cohesion during interkinesis of male meiosis [19, 20]. In pans1, chromosomes have been reported to undergo a normal reductional segregation at meiosis I, however during meiosis II, chromosomes lose centromeric cohesion prematurely prior to metaphase and as a consequence segregation occurs randomly resulting in the formation of unbalanced meiotic products and reduction in fertility. We confirmed the interkinesis phenotype of pans1 comprising loss of centromeric cohesion prematurely in meiosis II, prior to metaphase leading to unbalanced segregation (Fig. 1) and formation of defective microspores (Additional file 1: Figure S1): at metaphase I the majority of pans1 meiocytes showed 5 bivalents as in wild type; in contrast at metaphase II all (86/86) pans1 meiocytes showed 6–10 chromosomes indicating separation of sister chromatids, whereas for wild type, no meiocytes showed separation of sister chromatids at metaphase II (Table 1). Hence the major phenotype of pans1 is in meiosis II.Fig. 1


PATRONUS1 is expressed in meiotic prophase I to regulate centromeric cohesion in Arabidopsis and shows synthetic lethality with OSD1.

Singh DK, Spillane C, Siddiqi I - BMC Plant Biol. (2015)

Early loss of centromere cohesion in pans1 during meiosis II. Acid spreads of male meiotic chromosomes stained with DAPI. a-d wild type, e-ipans1. a,e Normal metaphase I. b, f Normal anaphase I. c Normal metaphase II d Normal anaphase II. g Early loss of cohesion in pans1 meiosis II prior to metaphase II. h Random movement of chromosomes in meiosis II in pans1. ipans1 defective metaphase I showing bipolar attachment (arrowheads) and univalents (*) in a subset of chromosomes
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4536785&req=5

Fig1: Early loss of centromere cohesion in pans1 during meiosis II. Acid spreads of male meiotic chromosomes stained with DAPI. a-d wild type, e-ipans1. a,e Normal metaphase I. b, f Normal anaphase I. c Normal metaphase II d Normal anaphase II. g Early loss of cohesion in pans1 meiosis II prior to metaphase II. h Random movement of chromosomes in meiosis II in pans1. ipans1 defective metaphase I showing bipolar attachment (arrowheads) and univalents (*) in a subset of chromosomes
Mentions: pans1 mutants of Arabidopsis have been recently reported to cause reduced fertility that arises from a defect in maintenance of centromeric cohesion during interkinesis of male meiosis [19, 20]. In pans1, chromosomes have been reported to undergo a normal reductional segregation at meiosis I, however during meiosis II, chromosomes lose centromeric cohesion prematurely prior to metaphase and as a consequence segregation occurs randomly resulting in the formation of unbalanced meiotic products and reduction in fertility. We confirmed the interkinesis phenotype of pans1 comprising loss of centromeric cohesion prematurely in meiosis II, prior to metaphase leading to unbalanced segregation (Fig. 1) and formation of defective microspores (Additional file 1: Figure S1): at metaphase I the majority of pans1 meiocytes showed 5 bivalents as in wild type; in contrast at metaphase II all (86/86) pans1 meiocytes showed 6–10 chromosomes indicating separation of sister chromatids, whereas for wild type, no meiocytes showed separation of sister chromatids at metaphase II (Table 1). Hence the major phenotype of pans1 is in meiosis II.Fig. 1

Bottom Line: Retention of sister centromere cohesion during meiosis I and its dissolution at meiosis II is necessary for balanced chromosome segregation and reduction of chromosome number.We show here that PANS1 protein is found mainly in prophase I of meiosis, with its level declining late in prophase I during diplotene.PANS1 also shows expression in dividing tissues.

View Article: PubMed Central - PubMed

Affiliation: Centre for Cellular and Molecular Biology (CSIR), Uppal Road, Hyderabad, 500007, India. dipesh@ccmb.res.in.

ABSTRACT

Background: Retention of sister centromere cohesion during meiosis I and its dissolution at meiosis II is necessary for balanced chromosome segregation and reduction of chromosome number. PATRONUS1 (PANS1) has recently been proposed to regulate centromere cohesion in Arabidopsis after meiosis I, during interkinesis. pans1 mutants lose centromere cohesion prematurely during interkinesis and segregate randomly at meiosis II. PANS1 protein interacts with components of the Anaphase Promoting Complex/Cyclosome (APC/C).

Results: We show here that PANS1 protein is found mainly in prophase I of meiosis, with its level declining late in prophase I during diplotene. PANS1 also shows expression in dividing tissues. We demonstrate that, in addition to the previously reported premature loss of centromere cohesion during interkinesis, pans1 mutants show partially penetrant defects in centromere cohesion during meiosis I. We also determine that pans1 shows synthetic lethality at the level of the sporophyte, with Omission of Second Division 1 (osd1), which encodes a known inhibitor of the APC/C that is required for cell cycle progression during mitosis, as well as meiosis I and II.

Conclusions: Our results show that PANS1 is expressed mainly in meiosis I where it has an important function and together with previous studies indicate that PANS1 and OSD1 are part of a network linking centromere cohesion and cell cycle progression through control of APC/C activity.

No MeSH data available.


Related in: MedlinePlus