5 - Biology and Biochemistry of Cultured Cell Lines: 1. Nucleic Acids

Abstract

This chapter focuses on the nucleic acids as they relate to cultured cell lines. In the synthesis of nucleic acids, animal cells are generally able to build up both the purine ring system and the pyrimidine nucleus of their constitutive nucleotides. Eukaryotic ribosomes are composed of ribonucleic acid (RNA), (approximately half of their total weight) in close association with a large variety of polypeptides. Their small subunit contains one molecule of 18S RNA, whereas the larger one comprises not only the so-called 28S RNA (more precisely, 26S RNA in Drosophila) and its hydrogen-bonded derivative(s) 5.8S RNA, but also one molecule of 5S RNA. This chapter begins with a discussion on nucleic acid metabolism and biosynthesis of nucleoside triphosphates. It proceeds with explaining concepts related to transcriptional control of ribosomal RNA genes, processing of 18S/26S gene transcripts, and maturation of 5S rRNA. The chapter also describes transcription map of mitochondrial deoxyribonucleic acid (DNA) and characterization of mitochondrial proteins. The chapter concludes with a discussion on DNA repair and sensitivity to mutagens and transcription apparatus and regulatory factors.