Champion Of Human Rights B R Ambedkar In 21st Century

Development in multicellular organisms results from growth and differentiation and is determined by a specific program of gene expression. In plants, environmental factors have a great influence on development via different signal transduction pathways that amplify the original signal and ultimately result in the activation or repression of certain genes. The synthesis of most eukaryotic proteins is regulated at the transcriptional level. Such a coordinated regulation depef!ds on the activity of a group of proteins generally called transcription factors, which are able to enhance or reduce the rate of transcription by facilitating the assembly of the initiation complex. A typical minimum promoter extends about 100 bp upstream of the transcription initiation site and includes several sequence elements named proximal promoter sequences. The. promoter sequences that interact with transcription factors are termed cis-acting elements while transcription factors that bind these cis-acting sequences are called trans-acting factors. Cis-acting elements that are far before the proximal promoter can exert either positive or negative control and are termed distal regulatory sequences. Distal cis-acting elements involved in gene regulation by hormones and other signaling agents are called response elements.