Mating type specific induction of cell wall lytic factor by agglutination of gametes in Chlamydomonas reinhardtii

1975 ◽  
Vol 67 (3) ◽  
pp. 623-637 ◽  
Author(s):  
U W Goodenough ◽  
R L Weiss

Cell fusion between mating type plus (mt+) and minus (mt-) gametes of Chlamydomonas reinhardtii is analyzed structurally and subjected to experimental manipulation. Cell wall lysis, a necessary prelude to fusion, is shown to require flagellar agglutination between competent gametes; glutaraldehyde-fixed gametes ("corpses") of one mating type will elicit both agglutination and cell wall lysis in the opposite mating type, whereas nonagglutinating impotent (imp) mutant strains are without effect. The fusion process is mediated by a narrow fertilization tubule which extends from the mt+ gamete and establishes contact with the mt- gamete. Formation of the tubule requires the "activation" of a specialized mating structure associated with the ml+ cell membrane; activation causes microfilaments to polymerize from the mating structure into the growing fertilization tubule. Mating structure activation is shown to depend on gametic flagellar agglutination; isoagglutination mediated by the lectin concanavalin A has no effect. Gametes carrying the imp-l mt+ mutation are able to agglutinate but not fuse with mt- cells; the imp-l gametes are shown to have structurally defective mating structures that do not generate microfilaments in response to gametic agglutination.


Planta ◽  
1991 ◽  
Vol 183 (1) ◽  
Author(s):  
J�rgen Voigt ◽  
Dieter Mergenhagen ◽  
Irmhild Wachholz ◽  
Elsbeth Manshard ◽  
Marianne Mix

2018 ◽  
Vol 28 (4) ◽  
pp. 169-178 ◽  
Author(s):  
Hyun-Ju Hwang ◽  
Yong Tae Kim ◽  
Nam Seon Kang ◽  
Jong Won Han

The algal cell wall is a potent barrier for delivery of transgenes for genetic engineering. Conventional methods developed for higher plant systems are often unable to penetrate or remove algal cell walls owing to their unique physical and chemical properties. Therefore, we developed a simple transformation method for <i>Chlamydomonas reinhardtii</i> using commercially available enzymes. Out of 7 enzymes screened for cell wall disruption, a commercial form of subtilisin (Alcalase) was the most effective at a low concentration (0.3 Anson units/mL). The efficiency was comparable to that of gamete lytic enzyme, a protease commonly used for the genetic transformation of <i>C. reinhardtii</i>. The transformation efficiency of our noninvasive method was similar to that of previous methods using autolysin as a cell wall-degrading enzyme in conjunction with glass bead transformation. Subtilisin showed approximately 35% sequence identity with sporangin, a hatching enzyme of <i>C. reinhardtii</i>, and shared conserved active domains, which may explain the effective cell wall degradation. Our trans­formation method using commercial subtilisin is more reliable and time saving than the conventional method using autolysin released from gametes for cell wall lysis.


Genetics ◽  
1984 ◽  
Vol 107 (4) ◽  
pp. 563-576
Author(s):  
Eva M Eves ◽  
Kwen-Sheng Chiang

ABSTRACT The transmission of two non-Mendelian drug resistance markers has been studied in crosses of Chlamydomonas reinhardtii involving diploids and aneuploids with different mating type genotypes. Under normal laboratory conditions for gametogenesis, mating and zygote maturation, the transmission pattern of the non-Mendelian markers sr-u-1 (resistance to streptomycin) and spr-u-1-27-3 (resistance to spectinomycin) is primarily determined by the mating type genotypes of the parental cells. Our results confirm and expand an earlier observation suggesting that an apparent codominant function of the female (mt  +) allele in regulating chloroplast gene transmission in meiosis appears to be distinct and separate from its recessive function in regulating mating behavior. The chloroplast DNA complement (as indexed by the number of extranuclear DNA-containing bodies) may exert a secondary effect on the transmission of these markers. Within a mating type group (mt+/mt- or mt-/mt-) a cell line with more chloroplast DNA tended to transmit its non-Mendelian markers more frequently than a cell line with less chloroplast DNA.


2007 ◽  
Vol 19 (1) ◽  
pp. 256-269 ◽  
Author(s):  
Katriina Keskiaho ◽  
Reija Hieta ◽  
Raija Sormunen ◽  
Johanna Myllyharju

1989 ◽  
Vol 109 (1) ◽  
pp. 247-252 ◽  
Author(s):  
U W Goodenough

Sexual adhesion between Chlamydomonas reinhardtii gametes elicits a rise in intracellular cAMP levels, and exogenous elevation of intracellular cAMP levels in gametes of a single mating type induces such mating responses as cell wall loss, flagellar tip activation, and mating structure activation (Pasquale, S. M., and U. W. Goodenough. 1987. J. Cell Biol. 105:2279-2292). Here evidence is presented that sexual adhesion mobilizes agglutinin to the flagellar surface, and that this mobilization can be induced by exogenous presentation of cAMP to gametes of a single mating type. It is proposed that Chlamydomonas adhesion entails a positive feedback system--initial contacts stimulate the presentation of additional agglutinin--and that this feedback is mediated by adhesion-induced cAMP generation.


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