Abstract:
:Differentiation-inducing factor 1 [DIF-1; 1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl)-hexan-1-one] induces stalk cell differentiation during Dictyostelium development. It is present as a gradient in the multicellular slug, its lowest concentration being in the anterior. Here we demonstrate the existence of a localized sink for DIF-1, also in the anterior of the slug, which could be responsible for generating the DIF-1 gradient. DIF-1 is metabolized extensively by developing cells, initially by a mono-dechlorination. We used an enzyme assay for DIF-1 dechlorinase to examine its distribution in the slug. DIF-1 dechlorinase activity is 30-fold higher in prestalk cells (largely anterior) compared with prespore cells (posterior) when these are separated from each other on Percoll density gradients. Dissection experiments showed that DIF-1 dechlorinase is 25-fold enriched in the anterior 13% of the slug compared with the rest. These experiments also showed that DIF-1 dechlorinase is more anterior-enriched than the standard prestalk markers, the ecmA and ecmB mRNAs. When cut from a slug, both prestalk and prespore fragments regulate to restore the missing cell type. Prespore fragments rapidly regain (by 30 min) a DIF-1 sink in their anteriors, and prestalk fragments restore a posterior zone with low DIF-1 dechlorinase by 4 hr after cutting. The reappearance of the DIF-1 sink in the anterior of prespore fragments is accomplished without detectable cell sorting and may, therefore, be in response to positional signals. Finally, a localized sink may provide a general way of producing a gradient of a signal substance in a developing embryo.
journal_name
Proc Natl Acad Sci U S Aauthors
Kay RR,Large S,Traynor D,Nayler Odoi
10.1073/pnas.90.2.487subject
Has Abstractpub_date
1993-01-15 00:00:00pages
487-91issue
2eissn
0027-8424issn
1091-6490journal_volume
90pub_type
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1989-09-01 00:00:00
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更新日期:2013-05-21 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2011-02-08 00:00:00
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更新日期:2007-05-29 00:00:00
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更新日期:2016-08-09 00:00:00