Interrupted gene

Cobucci-Ponzano, B., Trincone, A., Giordano, A., Rossi, M. and Moracci, M., (2003b). Identification of an archaeal alpha-L-fucosidase encoded by an interrupted gene. 

The precise function of introns is unknown. Nevertheless, there is some evidence that the exons, or coding sequences, give rise to structural domains in the final protein product. It is therefore considered that interrupted genes (the exons), as they are called, may reflect an evolutionary process in which combinations of various exons gave rise to different proteins through the joining of different protein domains. 

How can mammalian DNA be cloned and expressed by E. coli Recall that most mammalian genes are mosaics of introns and exons (Section 5.6). These interrupted genes cannot be expressed by bacteria, which lack the machinery to splice introns out of the primary transcript. However, this difficulty can be circumvented by causing bacteria to take up recombinant DNA that is complementary to mRNA. For example, proinsulin, a precursor of insulin, is synthesized by bacteria harboring plasmids that contain DNA complementary to mRNA for proinsulin (Figure 6.23). Indeed, bacteria produce much of the insulin used today by millions of diabetics. 

ND = not determined EBNA = Epstein-Barr virus nuclear antigen VGA = EBV capsid antigen BZLEl = EBV latency-interrupting gene involved in the viral lytic cycle MSX = methionine sul-foximine MIX = methotrexate. 

Another part of the picture in vertebrates and dowering plants is that genes are often not continuous segments of the DNA chain. Instead, a gene will begin in one small section of DNA called an exon, then be interrupted by a noncoding... 

The Coding Portions (Exons) of Most Eukaryotic Genes Are Interrupted by Introns... 

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