Breaking Report: Regulators of Hh Secretion

On my desk to read today? A report on a full-genome screen performed at the DRSC.

The authors include information that might be generally useful to screeners, particularly those performing or currently analyzing the results of luciferase-based assay readouts. The study also includes follow-up using in vivo RNAi.

Aikin et al. (2012) A Genome-Wide RNAi Screen Identifies Regulators of Cholesterol-Modified Hedgehog Secretion in Drosophila. PLoS One. 2012;7(3):e33665. PubMed ID: 22432040

Quote of the Week: Spirals

Of true organic spirals we have no lack. We think at once of horns of ruminants, and of still more exquisitely beautiful molluscan shells ... Closey related spirals may be traced in the florets of a sunflower; a true spiral, though not, by the way, so easy of investigation, is seen in the outline of a clodiform leaf; and yet again, we can recognise typical though transitory spirals in a lock of hair, in a staple of wool, in the coil of an elephant's trunk, in the 'circling spirals' of a snake, in the coils of a cuttle-fish's arm, or of a monkey's or a chameleon's tail.

Among such forms as these, and the many others which we might easily add to them, it is obvious that we have to do with things which, though mathematically similar, are biologically speaking fundamentally different; and not only are they biologically remote, but they are also physically different, in regard to the causes to which they are severally due.

Sir D'Arcy Thompson, On Growth and Form

Quote of the Week: Diversity in Development

If morphological diversity is all about development, and development results from genetic regulatory programs, then is the evolution of diversity directly related to the evolution of genetic regulatory programs? Simply put, yes. But to understand how diversity evolves, we must first understand the genetic regulatory mechanisms that operate in development. In other words, what is the genetic toolkit of development and how does it operate to build animals?

In, From DNA to Diversity

Carroll, Grenier and Weatherbee (2001, Blackwell Science; p.13).

Hoverfly RNAi

What I'm reading today:

Lemke & Schmidt (2009) Evidence for a composite anterior determinant in the hover fly Episyrphus balteatus (Syrphidae), a cyclorrhaphan fly with an anterodorsal serosa anlage. Development 136, 117-127. [PubMed 19060334]

Why I'm reading it:

I am nothing like an expert in the natural history of flies.  

But I do know this about hoverflies (syrphid flies), they're a popular macro photo pic on Flickr.  They frequent flowers and like bees, do some work as pollinators.

The cover photo on the January 2009 issue of Development shows a hoverfly.  

And the corresponding article includes some RNAi work. In a study of genes that support anterior-posterior patterning (including bicoid and caudal) in a hoverfly, the authors use injection of dsRNA (for RNAi-based knockdown) and mRNA (for ectopic expression) to explore gene function.

It's fun to see RNAi being used successfully in this kind of evolutionary study on a fly that lacks the history of genetics that D. melanogaster has behind it.  

Helps remind me that even though I rarely think about RNAi without high-throughput screens in mind, there are many other ways it's having an impact--on our understanding of Drosophila's many fly cousins and of biology more generally.