Question

indicate the expression pattern of hunchback and caudal mRNA at the completion of oogenesis

Answer 1

Maternal effect gene expressed in mother ovaries produce messenger RNAs which are placed in different regions of egg and they help in activating or repressing certain zygotic genes. Bicoid and Hunchback proteins regulate production of anterior structure while Nanos and Caudal regulates posterior part formation.

Hunchback and caudal mRNAs are distributed throughout the oocyte and after fertilization these mRNAs can be translated into protein. At anterior bicoid RNA is translated into Bicoid protein forming a gradient ans nanos is translated into Nanos protein at posterior end. Bicoid protein inhibits translation of caudal RNA allowing it to be synthesized only in posterior end whereas Nanos protein along with Pumilio protein binds to hunchback RNA preventing its translation at posterior part. Bicoid also increase the level of Hunchback protein at anterior end.