Structure and expression of ubiquitin genes in higher plants

Abstract

cDNA clones encoding ubiquitin were isolated from a barley leaf cDNA library using a mammalian ubiquitin cDNA clone as probe. The nucleotide sequence of one of the clones codes of 2.2 perfect repeats of the 76‐aminoacid‐long ubiquitin protein with an extra lysine residue at the C‐terminus. The barley ubiquitin amino acid sequence differs from the animal sequence at three positions and from the yeast sequence at two positions. The ubiquitin poly(precursor) are coded by a multigene family with 8 – 10 genes that produce four or five different size messengers between 700 and 2000 nucleotides in length. The large poly(A)‐rich RNAs are constitutively expressed in vegetative tissues whereas the 700‐nucleotide messenger(s) were only detected in tissues containing dividing cells. Copyright © 1986, Wiley Blackwell. All rights reserved