Chapter 17, Problem 1PDQ

(a)

Summary Introduction

To determine:

That how the idea emerges that the promoter and enhancer sequences control the initiation of transcription in eukaryotes

Introduction:

The gene expression is highly controlled starting at chromatin modification to protein stability. The modification in the DNA sequences and the histone proteins serves the major factor that influences the gene expression. The promoter sequences and the enhancer sequences are the initiating sequences present at the upstream of the DNA sequences. Modification in these sequences such as DNA methylation suppresses the gene expression that results in the silencing of the genes.

(b)

Summary Introduction

To determine:

That how the idea emerges that the eukaryotic transcription factors bind to DNA sequences at or near promoter regions

Introduction:

The transcription is the process in the encoding of genes to produce the mRNA that is complementary to that of gene sequences. It consists of three steps namely initiation, elongation and termination. The RNA polymerase serves as the major enzyme which carries outs the transcription process. Other transcription factors also play an important role in this process namely sigma factor, TFIIA, TFIIB, TFIIC, etc.

(c)

Summary Introduction

To determine:

That how the idea emerges that the double-stranded RNA molecules can control gene expression

Introduction:

There are several double-stranded RNA is involved in the regulation of gene expression. They are called as non-coding RNA since it does not code for any proteins. Examples are siRNA, miRNA, piRNA, etc. Small interfering RNA (siRNA) is the double-stranded noncoding RNA involved in the gene regulation by RNA interference mechanism. The enzyme Dicer cleaves the double-stranded siRNA into short single-stranded RNA that binds to the complementary base pairs within the genome to be silenced and denatures the mRNA.