Myc-n-max

First, consider this abstract:

Annu Rev Cell Dev Biol. 2000;16:653-99. The Myc/Max/Mad network and the transcriptional control of cell behavior. Grandori C, Cowley SM, James LP, Eisenman RN.

The Myc/Max/Mad network comprises a group of transcription factors whose distinct interactions result in gene-specific transcriptional activation or repression. A great deal of research indicates that the functions of the network play roles in cell proliferation, differentiation, and death. In this review we focus on the Myc and Mad protein families and attempt to relate their biological functions to their transcriptional activities and gene targets. Both Myc and Mad, as well as the more recently described Mnt and Mga proteins, form heterodimers with Max, permitting binding to specific DNA sequences. These DNA-bound heterodimers recruit coactivator or corepressor complexes that generate alterations in chromatin structure, which in turn modulate transcription. Initial identification of target genes suggests that the network regulates genes involved in the cell cycle, growth, life span, and morphology. Because Myc and Mad proteins are expressed in response to diverse signaling pathways, the network can be viewed as a functional module which acts to convert environmental signals into specific gene-regulatory programs.

Keeping in mind that front-loading allows us to predict that major evolutionary transitions would be indebted to preadaptations, consider this recent finding:

More Epithelial Nudging

If you’ll recall, back in December, I provided evidence that unicellular organisms were endowed with components (beta catenins) that served as preadaptations to nudge epithelial tissue into existence when needed.

Well, feast your eyes on a paper that was published in Science just a couple of weeks ago.

Introns and Metazoans again

Recall that I hypothesized that introns have played a key role in facilitating metaozoan evolution.  Here’s some more support support for that hypothesis:

Metazoan transcription factors predate metazoans

I run across many papers that support the hypothesis of front-loading, but never seem to find the time these days to write up blog entries that explain the findings and how they relate to FLE.  So instead of just sitting on them, I thought I would share them by posting the abstracts.  In the future, I hope to comment on them.  If you have read the book or follow this blog, you should be able to pick out the relevance of the findings.  So here’s the first one about transcription factors, which are proteins that regulate the expression of genes: