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Human Intronless Genes and their Associated Diseases

  1. Ewa A Grzybowska

Published Online: 15 MAY 2013

DOI: 10.1002/9780470015902.a0025005

eLS

eLS

How to Cite

Grzybowska, E. A. 2013. Human Intronless Genes and their Associated Diseases. eLS. .

Author Information

  1. Cancer Center Institute, Warsaw, Poland

Publication History

  1. Published Online: 15 MAY 2013

Abstract

Intronless genes (IGs) are common in single-celled eukaryotes, whereas in metazoans they comprise only a small percentage of genes. The distribution of human IGs among functional groups is different from the distribution in the whole human genome: IGs mostly encode signal-transducing molecules, such as G-protein coupled receptors, which are the largest family within IGs; the second largest group encodes histones. IGs often exhibit tissue-specific expression, especially in testis and brain. Accordingly, mutations in IGs are predominantly associated with neurological and developmental disorders, as well as several types of cancer. From the evolutionary viewpoint, most IGs are relatively recent and emerged by retroposition. Processing of messenger ribonucleic acids (mRNAs) encoded by natural IGs is independent of splicing, and resembles the processing of some unspliced viral transcripts. In contrast to random RNA sequences, mRNAs encoded by natural IGs are stable and efficiently accumulate in the cytoplasm.

Key Concepts:

  • Human IGs constitute about 3% of the human genome.

  • Human IGs encode mostly signalling molecules and histones.

  • IG-associated diseases comprise mostly neurological and developmental disorders and some types of cancer.

  • IGs often display tissue-specific expression, usually in the nervous system and testis.

  • Most human IGs emerged in the process of retroposition.

  • Natural IGs have evolved their own means of processing, independent of splicing.

Keywords:

  • intronless genes;
  • GPCR;
  • signal-transducing molecules;
  • histones;
  • retroposition;
  • mRNA nuclear export