Divergent neural beta tubulin from the Antarctic fish Notothenia coriiceps neglecta: potential sequence contributions to cold adaptation of microtubule assembly

Cell Motil Cytoskeleton. 1993;24(3):156-66. doi: 10.1002/cm.970240303.

Abstract

The cytoplasmic microtubules of the cold-adapted Antarctic fishes, unlike those of homeotherms and temperate poikilotherms, assemble and function at body temperatures in the range -1.8 to +2 degrees C. To determine whether alterations to the primary sequence of beta tubulin may contribute to enhancement of microtubule assembly at cold temperatures, we have cloned and sequenced a 1.8-kilobase neural beta-chain cDNA, Ncn beta 1, from an Antarctic rockcod, Notothenia coriiceps neglecta. Based on nucleotide sequence homology, Ncn beta 1 probably corresponds to a class-II beta-tubulin gene. The 446-residue beta chain encoded by Ncn beta 1 is closely related (sequence homology approximately 95%) both to the neural class-I/II isotypes and to the neural/testicular class-IV variants of higher vertebrates, but the sequence of its carboxy-terminal isotype-defining region (residues 431-446) has diverged markedly (> or = 25% change relative to the I/II/IV referents). Furthermore, the Ncn beta 1 polypeptide contains six unique amino-acid substitutions (five conservative, one nonconservative) not found in other vertebrate brain isotypes, and the carboxy-terminal region possesses a unique tyrosine inserted at position 442. We conclude that Ncn beta 1 encodes a class-II beta tubulin that contains sequence modifications, located largely in its interdimer contact domain, that may contribute to cold adaptation of microtubule assembly.

Publication types

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

MeSH terms

  • Acclimatization / genetics*
  • Amino Acid Sequence
  • Animals
  • Antarctic Regions
  • Base Sequence
  • Codon
  • Cold Climate*
  • DNA / genetics
  • Fishes / genetics*
  • Microtubules / physiology*
  • Molecular Sequence Data
  • Multigene Family
  • Tubulin / genetics*

Substances

  • Codon
  • Tubulin
  • DNA

Associated data

  • GENBANK/S57698
  • GENBANK/S68271
  • GENBANK/Z25423
  • GENBANK/Z25424
  • GENBANK/Z25425
  • GENBANK/Z25426
  • GENBANK/Z25427
  • GENBANK/Z25428
  • GENBANK/Z25429
  • GENBANK/Z25430