Two versions of the gene encoding the 41-kilodalton subunit of the telomere binding protein of Oxytricha nova.
Macronuclear chromosomes of the ciliated protozoan Oxytricha nova terminate with a single-stranded (T4G4)2 overhang. The (T4G4)2 telomeric overhang is tenaciously bound by a protein heterodimer. We have cloned and sequenced the gene encoding the 41-kDa subunit of this telomere binding protein. The predicted amino acid sequence comprises two distinct regions, a carboxyl-terminal two-thirds that is 23% lysine and bears similarity to histone H1 and an amino-terminal one-third containing a hydrophobic stretch of about 15 amino acids. Two macronuclear versions of the gene differ in nucleotide sequence at several positions, but the derived polypeptides differ only at a single position, Ser-110 or Ala-110. Both versions harbor a small intron. The existence of this intron demonstrates that, despite the elimination of 95% of the micronuclear genome from the developing macronucleus, at least some noncoding DNA is retained during macronuclear development of hypotrichous ciliates.
Department of Molecular, Cellular and Developmental Biology, Howard Hughes Medical Institute, University of Colorado, Boulder 80309.
B J
BJ
Hicke
D W
DW
Celander
G H
GH
MacDonald
C M
CM
Price
T R
TR
Cech
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016798:Ciliophora / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification; D005784:Gene Amplification; D015723:Gene Library; D005796:Genes; D007256:Information Systems; D007438:Introns; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010449:Peptide Mapping; D011487:Protein Conformation; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid
D004268:DNA-Binding Proteins; D015345:Oligonucleotide Probes; D012313:RNA; D004247:DNA