Question

What is the role of protein Bicoid in the Anterior-Posterior patterning in early Drosophila embryo? (hint: 3 things)

Answer 1

Bicoid is a maternal mRNA that forms the anterior-posterior patterning in early drosophila embryo. As fertilisation occurs, bicoid mRNA is translated into protein. It's concentration is highest at the anterior region and decreases towards posterior end, thus, forming a gradient. Caudal is another maternal mRNA, which forms the posterior side of the embryo. Before fertilisation, caudal is distributed throughout the egg, but soon after fertilisation, as it begins translation, it is inhibited at the anterior side by the bicoid protein. Thus, caudal protein is limited only to the posterior side. Bicoid at the anterior side also stimulates expression of hunchback gene and these two proteins together form the head and thorax in drosophila, whereas, nanos and caudal proteins form the abdomen and tail at the posterior end.