Online ISSN : 1348-7019
Print ISSN : 0011-4545
HAP2/GCS1 Is Involved in the Sexual Reproduction System of the Marine Macroalga Ulva compressa (Ulvales, Chlorophyta)
Tomokazu YamazakiMikiya EndoKan ItoRyogo SuzukiShuhei OtaKazuyoshi KuwanoShinichi MiyamuraAtsushi ToyodaShigeyuki Kawano
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2014 Volume 79 Issue 4 Pages 575-584


Gamete fusion or fertilization is one of the most important steps in sexual reproduction. HAP2/GCS1 is a potential gamete membrane fusion component. We analyzed whole genome sequences of two strains with opposite mating types (mt and mt+) in the marine macroalga Ulva compressa and found that identical genomic regions homologous with HAP2/GCS1 existed in their draft genome sequences. Although an RNA-Seq analysis revealed that a variety of transcripts was expressed from the two regions containing HAP2/GCS1 in both the gamete and gametophyte of the mt and mt+ genotypes, a putative transcript coding a protein containing a HAP2–GCS1 domain was identified only in the mt gamete. Immunofluorescence observations using an antibody against the putative HAP2/GCS1 demonstrated that the HAP2/GCS1 translational products localized to the cellular surface between the two flagella at a potential site for the mt mating structure. The antibody inhibited mating of the mt gamete with the mt+ gamete in U. compressa. Our data suggest that HAP2/GCS1 functions in the mt gamete and plays a role in gamete fusion. Moreover, the specific function of HAP2/GCS1 in the mt mating type may be regulated by an alternative splicing mechanism in U. compressa.

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© 2014 The Japan Mendel Society
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