don't crack down bioluminescence imaging

The laboratory that discovered leptin have recently reported a BAC transgenic mouse line that express luciferase under the control of leptin promoter elements. They showed that bioluminescence imaging faithfully recapitulates regulation of leptin mRNA in different condition of fasting/fed regimens in normal/obese background with/out leptin withdrawal. So, by in vivo imaging they now strive to characterize the still unknown cellular program responsible for restoration of adipose tissue after weight loss. Best wishes. I'm a strong supporter of reporter imaging in animal research (here, here and here). However, this latter model pose me some doubts. Even if I recognize the finest quality to study gene expression chronology in a living animal, I wonder about the necessity and the economy to make research with surrogate markers (luciferase) of a single gene expression (leptin). Signalling networks are so robust and redundant!

In my humble opinion, luciferase reporter mice are better exploited to track responsive elements of critical transcription factor, in that case the photon emission would be a surrogate marker of the final result of one/more signalling cascades and not just the mirror of one of our 30,000 genes. That's much informative. Of course, then you need some deconvolution, but you can reasonably get the dissection of your pathway by crossing your reporter mouse into a KO background. Definitively, to study mRNA expression in a tissue, I prefer a hierarchical clustering of quantitative PCR dataset (of different genes), chiefly with new technologies (here and here). Yes, this is just my personal naive opinion, feel free to fill my gaps.


K. Birsoy, A. Soukas, J. Torrens, G. Ceccarini, J. Montez, M. Maffei, P. Cohen, G. Fayzikhodjaeva, A. Viale, N. D. Socci, J. M. Friedman (2008). Cellular program controlling the recovery of adipose tissue mass: An in vivo imaging approach Proceedings of the National Academy of Sciences, 105 (35), 12985-12990 DOI: 10.1073/pnas.0805621105

this is another example of BLI crack down