Cloning and sequencing of an alpha-tubulin cDNA from Artemia franciscana: evidence for translational regulation of alpha-tubulin synthesis.
The brine shrimp, Artemia franciscana, exhibits a limited number of tubulin isotypes which change little during early postgastrula growth. In order to better understand the synthesis of alpha-tubulins during Artemia development, a cDNA termed alphaAT1 was cloned and sequenced. Alignment analyses revealed that the polypeptide encoded by alphaAT1 is similar to alpha-tubulins from other species. Hybridization of alphaAT1 to restriction-digested DNA on Southern blots produced a simple banding pattern, indicating that Artemia have a small number of alpha-tubulin genes. Probing of Northern blots demonstrated an abundant supply of alpha-tubulin mRNA in dormant cysts, emerging nauplii and instar I larvae. However, it was not until instar I larvae were produced that the amount of polysomal alpha-tubulin mRNA increased, suggesting that synthesis of the tubulin corresponding to alphaAT1 is translationally controlled. This work provides one of the few examples where tubulin synthesis is thought to be translationally regulated. Moreover, when considered in the light of previous analyses, the findings imply that cell differentiation in postgastrula Artemia and the diversification of microtubule function certain to accompany this process occur with little or no change in alpha-tubulin composition.
Zheng
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Y
Dalhousie University, Biology Department, Halifax, N.S. B3H 4J1, Canada.
Roy
P J
PJ
Liang
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P
MacRae
T H
TH
D000595:Amino Acid Sequence; D000818:Animals; D001156:Artemia / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014404:Tubulin / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*
D018076:DNA, Complementary; D011994:Recombinant Proteins; D014404:Tubulin