Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article Full Text (PDF, 633K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Wells, W. A. Search for Related Content PubMed Articles by Wells, W. A. Social Bookmarking                            What's this?

Difference drives division

DPP pathway changes in one area (green) affects division (red) in other areas. IRVINE/ELSEVIER

Morphogens that spread from a point or line source are useful for patterning and for defining the outer bounds of a tissue. How to convert such a gradient into uniform cellular growth is, however, far from obvious. Can a pro-growth morphogen avoid encouraging excessive growth near its source and inadequate growth further away?Dragana Rogulja and Kenneth Irvine (Rutgers, Piscataway, NJ) now provide one possible solution for cells that will become fly wings. The cells, they find, make their division decision in response to a gradient rather than absolute concentrations of the Decapentaplegic (DPP) morphogen.

The Rutgers group expressed or repressed the DPP pathway in small clones. In both cases they saw new cell division both within the clone and in neighboring areas. This nonautonomous growth had not been evident in previous experiments, probably because the earlier experiments used expression systems with a long lag time. The new experiments used drug-inducible expression to get tighter temporal control.

The researchers believe that cells measure the difference between their own DPP expression level and that of their neighbor, and go through cell division only if there is a difference. This growth effect may be able to spread for several cell diameters both back into the DPP-expressing clone and out into the area expressing lower levels of DPP. Intercell comparisons could be made, for example, by cells expressing receptors that bind homophilically to their partners in a neighboring cell, but signal if there are no more binding partners available.

Further from the DPP source, the gradient effect drops away, probably because in wild-type tissue this area would experience extremely shallow gradients of DPP. The cells in this area seem to depend more on the absolute values of DPP for their instructions.

Reference:

Rogulja, D., and K.D. Irvine. 2005. Cell. 123:449–461.[CrossRef][Medline]

William A. Wells

wellsw{at}rockefeller.edu

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This Article Full Text (PDF, 633K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Wells, W. A. Search for Related Content PubMed Articles by Wells, W. A. Social Bookmarking                            What's this?