Question

In $Drosophila$, a set of homeotic genes which control body plan at the time of organ differentiation is known as

• A. TATA box
• B. Homeobox
• C. Pribnow box
• D. All of the above

Answer 1

Answer: (B)

Homeobox

Homeodomain is a DNA-binding domain having 60 amino acids that is present in transcription factors which regulate expression of homeotic genes, hence, the name homeodomain. These genes regulate the development of body patterns and known as homeogenes. The DNA sequence that encodes this domain is known as the homeobox.

The Pribnow box is the consensus sequence of six nucleotides "TATAAT" and forms the essential part of a promoter site on bacterial DNA. This site is recognized and bound by RNA polymerase subunit during transcription initiation. Since, $Drosophila$ is an eukaryotic organism, it can not have pribnow box which is prokaryotic promoter site.
The TATA box is a DNA sequence in promoter region of archaeal and eukaryotic housekeeping genes. These genes are the constitutive genes that maintain the basic cellular function and are expressed under normal physiological conditions. Hence, TATA box does not regulate the homeotic genes. Thus, correct answer is option B.