The
Burmese python's body undergoes massive reconstruction followed by complete
deconstruction every time it eats. Within three days of eating, its organs
expand up to double in size and its metabolism and digestive processes increase
10- to 44-fold. Ten days after eating, the snake's meal is digested and these
changes have reversed, allowing the body to shrink and return back to its
pre-meal state. In a new study published in Physiological
Genomics, a team of U.S. researchers tracked in detail how this extreme
makeover is controlled by changes in gene expression.
The
Burmese python's extreme physiology is fascinating to study because it gives
unique insight into how vertebrates control organ growth and function, the
researchers wrote. Although the Burmese python's body shape is distinct from
other vertebrates, including humans, its organs operate the same. This means
findings from snakes can be applied to understanding the human body and
potentially developing new therapies for human diseases, the researchers said.
In this
study, the research team focused on the small intestine, which doubles in mass
and nutrient-absorption rate during digestion. The researchers found that the
expression of at least 2,000 genes changed after the snake ate. Surprisingly,
most of the changes occurred soon after eating -- within six hours. Genes that
changed included those involved with the intestine's structure and nutrient
absorption, cell division and cell death. The patterns of gene expression
matched and often preceded physiological changes in the intestine, the researchers
wrote. The gene expression patterns, like the structural changes, then returned
to pre-eating state within 10 days after eating, "indicating a tight
association between differential gene expression and the rapid and cyclic
physiological remodeling of the intestine," the researchers said.
According
to the researchers, this is the first study to link the extreme and rapid
eating-induced changes of the Burmese python's intestines directly to changes
in gene expression, and also the first to show how quickly gene expression
changed. The study also found that some of the morphing genes in the python's
intestine, notably those in a signaling pathway called WNT, were genes that
were involved in intestinal and other cancers. This suggests that "the
python intestine may represent a valuable model for studying the interactions
of metabolism with the regulation of cell division/death and WNT signaling
relevant to cancer," the researchers said.
Citation
Andrew
AL, Card DC, Ruggiero RP, Schield DR, Adams RH, Pollock DD, Secor SM, Castoe TA. (2015)
Rapid changes in gene expression direct
rapid shifts in intestinal form and function in the Burmese python after
feeding. Physiological Genomics, 47 (5): 147 DOI: 10.1152/physiolgenomics.00131.2014