Question

Suppose the protein specified by bicoid was injected into drosophila embryos, so that a high concentration was present everywhere in the embryo. what might be the result of such an experiment

Answer 1

I believe that answer would be that the embryos would show no development of posterior regions. Bicoid protein is a transcription factor and also a morphogen. It has a DNA binding homeodomain that binds both DNA and the nanos mRNA. It binds a specific RNA sequence in the 3' untranslated region, called the Bicoid 3'-UTR regulatory element, of caudal mRNA and blocks translation. 

Answer 2

The right answer is The embryos would show no development of posterior regions.

Bicoïd is a maternal-effect gene deposited in the oocyte by the female during oogenesis. It is expressed at the level of the egg and is involved in the development of the anteroposterior axis in Drosophila and more precisely in the early determination of the development pattern of the anterior region in the embryo. This area develops later to form the head and thoracic part in adults.

It is also the first known morphogen, whose decreasing concentration gradient from the anterior part of the oocyte, specifies different regions in the embryo and allows the formation of its axes of polarity (thus its presence in the whole of the embryo implies that there is no development of the posterior part).

Bicoïd also has a homeobox that encodes a homeodomain. This sequence is involved in the regulation of the expression of several genes that lie along the anteroposterior axis of Drosophila. The protein, therefore, acts either as a transcription factor that stimulates the synthesis of mRNAs from DNA or as an inhibitor of the translation of mRNAs into proteins, depending on the genes involved.