PATRONUS1 is expressed in meiotic prophase I to regulate centromeric cohesion in Arabidopsis and shows synthetic lethality with OSD1.
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.
Centre for Cellular and Molecular Biology (CSIR), Uppal Road, Hyderabad, 500007, India. dipesh@ccmb.res.in.
Dipesh Kumar
DK
Singh
Genetics and Biotechnology Lab, Plant and AgriBiosciences Research Centre (PABC), Botany and Plant Sciences, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland. charles.spillane@nuigalway.ie.
Charles
C
Spillane
Centre for Cellular and Molecular Biology (CSIR), Uppal Road, Hyderabad, 500007, India. imran@ccmb.res.in.
Imran
I
Siddiqi
D064173:Anaphase-Promoting Complex-Cyclosome / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics; D002503:Centromere / Q000235:genetics; D020090:Chromosome Segregation; D049469:Meiotic Prophase I
D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C577069:OSD1 protein, Arabidopsis; C000589331:patronus protein, Arabidopsis; D064173:Anaphase-Promoting Complex-Cyclosome