How is controlled the expression of the first homeotic gene if

Anyone? this is maybe a really stupid question but i'm really intrigued

>>8450080
Rephrase your question becaue people don't understand it; 'exprimed' is not the right word in that context.

>>8450080
>>8450212

Yeah, I'm not sure what you're asking

>>8450212
>>8450428

Sorry, my bad, I meant "expressed"

Homeotic genes regulate the development of the structures of the anteroposterior axis. They are expressed chronologically, so the first homeotic gene will code for the most anterior region of the axis.

So, how its expression (of the first homeotic gene) is regulated if there is not yet any other embryonic gene expressed?

If there are not yet any other embryonic gene expressed, It would mean that there aren't either transcriptional factors.

Hope this time I expressed myself better.

There are other positional genes expressed.
The hox genes are regulated by combinatorial control based the concentration of the various segmentation proteins. These are our maternal effect, gap, pair rule and polarity proteins.
So like the maternal effect proteins could be an activator, and maybe two of the gap genes are activators and some other gap genes are inhibitors. In the specific segment where we get the right combination of these guys this hox gene can be transcribed