Molecular Characterization of a Zygote Wall Protein: An Extensin-Like Molecule in Chlamydomonas reinhardtii

• Published in: The Plant cell Vol. 1; no. 9; pp. 901 - 911
• Main Authors: Woessner, Jeffrey P., Goodenough, Ursula W.
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Physiologists 01.09.1989
• Subjects: Amino Acid Sequence; Amino acids; Animals; Antibodies; Base Sequence; Cell Wall - metabolism; Cell walls; Chlamydomonas reinhardtii - genetics; Complementary DNA; DNA; Gels; Glycoproteins - chemistry; Glycoproteins - genetics; Glycoproteins - metabolism; Hydroxyproline - chemistry; Messenger RNA; Molecular Sequence Data; Plant cells; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Precipitin Tests; Restriction Mapping; RNA; Zygote - metabolism; Zygotes
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.1.9.901

The green alga Chlamydomonas reinhardtii elaborates two biochemically and morphologically distinct cell walls during its life cycle: one surrounds the vegetative and gametic cell and the other encompasses the zygote. Hydroxyproline-rich glycoproteins (HRGPs) constitute a major component of both walls. We describe the isolation and characterization of a zygote-specific gene encoding a wall HRGP. The derived amino acid sequence of this algal HRGP is similar to those of higher plant extensins, rich in proline and serine residues and possessing repeating amino acid motifs, notably $X({\rm Pro})_{3}$ and $({\rm Ser}\text{-}{\rm Pro})_{n}$. Antiserum against this zygote wall protein detected common epitopes in several other zygote polypeptides, at least one of which is also encoded by a zygote-specific gene. We conclude that there is one set of HRGP wall genes expressed only in zygotes and another set that is specific to vegetative and gametic cells.