TY - JOUR

T1 - LOSP

T2 - A putative marker of parasperm lineage in male reproductive system of the prosobranch mollusk Littorina obtusata

AU - Lobov, Arseniy A.

AU - Maltseva , Arina L.

AU - Starunov, Viktor V.

AU - Babkina, Irina Y.

AU - Ivanov, Vadim A.

AU - Mikhailova, Natalia A.

AU - Granovitch, Andrey I.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Reproductive isolation is the key attribute of biological species and establishment of the reproductive barriers is an essential event for speciation. Among the mechanisms of reproductive isolation, gamete incompatibility due to the variability of gamete interaction proteins may drive fast divergence even in sympatry. However, the number of available models to study this phenomenon is limited. In case of internally fertilized invertebrates, models to study gamete incompatibility and sperm competition mechanisms are restricted to a single taxon: insects. Here, we propose a group of closely related Littorina species as a new model for such studies. Particularly since periwinkles are already thoroughly studied in terms of morphology, physiology, ecology, phylogeny, and ecological speciation. Earlier, we have identified the first species-specific Littorina sperm protein (LOSP) with no known conservative domains or homologies. LOSP is relatively abundant component of sperm extracts and might be involved in gamete incompatibility. Here, we characterize its definitive localization and mRNA expression pattern in the male reproductive system by immunocytochemistry and RNA in situ hybridization. We demonstrate that LOSP distribution is limited to the parasperm cells. Losp gene expression occurs only at the early stages of parasperm development. The protein is stored within granules of mature parasperm and, most likely, is released after ejaculation inside female reproductive system. Thus, LOSP is the only described molluscan paraspermal protein to date, and there is a possibility for LOSP to be involved in gamete incompatibility since heterospermy is a common phenomenon among Littorina.

AB - Reproductive isolation is the key attribute of biological species and establishment of the reproductive barriers is an essential event for speciation. Among the mechanisms of reproductive isolation, gamete incompatibility due to the variability of gamete interaction proteins may drive fast divergence even in sympatry. However, the number of available models to study this phenomenon is limited. In case of internally fertilized invertebrates, models to study gamete incompatibility and sperm competition mechanisms are restricted to a single taxon: insects. Here, we propose a group of closely related Littorina species as a new model for such studies. Particularly since periwinkles are already thoroughly studied in terms of morphology, physiology, ecology, phylogeny, and ecological speciation. Earlier, we have identified the first species-specific Littorina sperm protein (LOSP) with no known conservative domains or homologies. LOSP is relatively abundant component of sperm extracts and might be involved in gamete incompatibility. Here, we characterize its definitive localization and mRNA expression pattern in the male reproductive system by immunocytochemistry and RNA in situ hybridization. We demonstrate that LOSP distribution is limited to the parasperm cells. Losp gene expression occurs only at the early stages of parasperm development. The protein is stored within granules of mature parasperm and, most likely, is released after ejaculation inside female reproductive system. Thus, LOSP is the only described molluscan paraspermal protein to date, and there is a possibility for LOSP to be involved in gamete incompatibility since heterospermy is a common phenomenon among Littorina.

KW - heterospermy

KW - Littorina

KW - LOSP

KW - parasperm

KW - reproductive isolation

KW - reproductive proteins

KW - seminal fluids

UR - http://www.scopus.com/inward/record.url?scp=85046805566&partnerID=8YFLogxK

U2 - 10.1002/jez.b.22803

DO - 10.1002/jez.b.22803

M3 - Article

VL - 330

SP - 193

EP - 201

JO - Journal of Experimental Zoology Part B: Molecular and Developmental Evolution

JF - Journal of Experimental Zoology Part B: Molecular and Developmental Evolution

SN - 1552-5007

IS - 4

ER -