Linked Life Data

9914155

Source:http://linkedlifedata.com/resource/pubmed/id/9914155

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1999-7-20
pubmed:abstractText
The phosphatase inhibitor okadaic acid accelerates meiotic events in rodent germ cells in culture. Isolated pachytene spermatocytes treated with okadaic acid proceed to a metaphase I arrest in a few hours as opposed to the similar process in vivo, which requires several days. Leptotene/zygotene spermatocytes cannot be activated in this way, suggesting that okadaic acid enables cells to bypass a sensor of the meiotic progression, which is pachytene specific. We monitored the chromosome behaviour accompanying the transition to metaphase I in rat spermatocytes with antibodies against COR1/SCP3, a component of the meiotic chromosome cores, and against the synaptic protein, SYN1/SCP1. Okadaic acid induced a rapid synaptonemal complex dissolution and bivalent separation, followed by chromosome condensation and chiasmata formation, similar to the succession of events in untreated cells. The similarity between meiosis I induced with okadaic acid and the meiosis I events in vivo extends to the dissolution of the nuclear membrane and the disappearance of the microtubule network at the onset of metaphase I. This cell culture system provides a model for the in vivo transition from pachytene to metaphase I and therefore can be used in the study of this transition at the molecular level. The effect of okadaic acid is most likely mediated by the activation of tyrosine kinases, as addition of genistein, a general tyrosine kinase inhibitor, completely abolishes the observed effect of okadaic acid on chromosome metabolism. The okadaic acid-induced progression to the metaphase I arrest is not affected by the inhibition of protein synthesis. However, pachytene spermatocytes incubated in the presence of protein synthesis inhibitors for 6 hours show loss of synapsis which is abnormal in that it is not accompanied by chiasmata formation. The two meiosis-specific proteins, SYN1/SCP1 and COR1/SCP3, are efficiently phosphorylated in vitro by extracts from isolated pachytene cells. Extracts from cells that have reached metaphase I upon okadaic acid treatment, with concomitant displacement of SYN1/SCP1 and COR1/SCP3 from their chromosomes, do not have this capability. These data support the hypothesis that phosphorylation of SYN1/SCP1 and COR1/SCP3 targets their removal from the chromosomes and that activity of the kinases involved correlates with the presence of these two proteins on the chromosomes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9533
pubmed:author
pubmed:issnType
Print
pubmed:volume
112 ( Pt 4)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
423-34
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:9914155-Animals, pubmed-meshheading:9914155-Chromosomes, pubmed-meshheading:9914155-Enzyme Inhibitors, pubmed-meshheading:9914155-Genistein, pubmed-meshheading:9914155-Immunohistochemistry, pubmed-meshheading:9914155-Male, pubmed-meshheading:9914155-Meiosis, pubmed-meshheading:9914155-Metaphase, pubmed-meshheading:9914155-Microtubules, pubmed-meshheading:9914155-Nuclear Proteins, pubmed-meshheading:9914155-Okadaic Acid, pubmed-meshheading:9914155-Phosphorylation, pubmed-meshheading:9914155-Protein Biosynthesis, pubmed-meshheading:9914155-Protein Synthesis Inhibitors, pubmed-meshheading:9914155-Protein-Tyrosine Kinases, pubmed-meshheading:9914155-Rats, pubmed-meshheading:9914155-Spermatocytes, pubmed-meshheading:9914155-Subcellular Fractions, pubmed-meshheading:9914155-Synaptonemal Complex, pubmed-meshheading:9914155-Testis, pubmed-meshheading:9914155-Time Factors
pubmed:year
1999
pubmed:articleTitle
Meiotic activation of rat pachytene spermatocytes with okadaic acid: the behaviour of synaptonemal complex components SYN1/SCP1 and COR1/SCP3.
pubmed:affiliation
Department of Biology, York University, Toronto, Ontario, M3J 1P3 Canada. moens@yorku.ca
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't