Structure, chromosome location, and expression of the human gamma-actin gene: differential evolution, location, and expression of the cytoskeletal beta- and gamma-actin genes

Mol Cell Biol. 1988 Apr;8(4):1775-89. doi: 10.1128/mcb.8.4.1775-1789.1988.

Abstract

The accumulation of the cytoskeletal beta- and gamma-actin mRNAs was determined in a variety of mouse tissues and organs. The beta-isoform is always expressed in excess of the gamma-isoform. However, the molar ratio of beta- to gamma-actin mRNA varies from 1.7 in kidney and testis to 12 in sarcomeric muscle to 114 in liver. We conclude that, whereas the cytoskeletal beta- and gamma-actins are truly coexpressed, their mRNA levels are subject to differential regulation between different cell types. The human gamma-actin gene has been cloned and sequenced, and its chromosome location has been determined. The gene is located on human chromosome 17, unlike beta-actin which is on chromosome 7. Thus, if these genes are also unlinked in the mouse, the coexpression of the beta- and gamma-actin genes in rodent tissues cannot be determined by gene linkage. Comparison of the human beta- and gamma-actin genes reveals that noncoding sequences in the 5'-flanking region and in intron III have been conserved since the duplication that gave rise to these two genes. In contrast, there are sequences in intron III and the 3'-untranslated region which are not present in the beta-actin gene but are conserved between the human gamma-actin and the Xenopus borealis type 1 actin genes. Such conserved noncoding sequences may contribute to the coexpression of beta- and gamma-actin or to the unique regulation and function of the gamma-actin gene. Finally, we demonstrate that the human gamma-actin gene is expressed after introduction into mouse L cells and C2 myoblasts and that, upon fusion of C2 cells to form myotubes, the human gamma-actin gene is appropriately regulated.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / genetics*
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Biological Evolution*
  • Chromosome Mapping
  • Chromosomes, Human, Pair 17*
  • Chromosomes, Human, Pair 7*
  • Cytoskeleton / metabolism*
  • DNA Restriction Enzymes
  • Genes*
  • Humans
  • Kidney / metabolism
  • Liver / metabolism
  • Male
  • Mice
  • Molecular Sequence Data
  • Muscles / metabolism
  • Nucleotide Mapping
  • Organ Specificity
  • RNA, Messenger / genetics
  • Testis / metabolism
  • Transcription, Genetic*

Substances

  • Actins
  • RNA, Messenger
  • DNA Restriction Enzymes

Associated data

  • GENBANK/M19283