Molecular characterization and expression profiling of transformer 2 and fruitless-like homologs in the black tiger shrimp, Penaeus monodon

Prawporn Thaijongrak; Charoonroj Chotwiwatthanakun; Phaivit Laphyai; Anuphap Prachumwat; Thanapong Kruangkum; Prasert Sobhon; Rapeepun Vanichviriyakit

doi:10.7717/peerj.12980

Molecular characterization and expression profiling of transformer 2 and fruitless-like homologs in the black tiger shrimp, Penaeus monodon

PeerJ. 2022 Feb 17:10:e12980. doi: 10.7717/peerj.12980. eCollection 2022.

Authors

Prawporn Thaijongrak^{1

2

3}, Charoonroj Chotwiwatthanakun^{1

4}, Phaivit Laphyai^{1

2}, Anuphap Prachumwat^{1

5}, Thanapong Kruangkum^{1

2}, Prasert Sobhon², Rapeepun Vanichviriyakit^{1

2}

Affiliations

¹ Center of Excellence for Shrimp Molecular Biology and Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand.
² Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, Thailand.
³ Department of Clinical Sciences and Public Health, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom, Thailand.
⁴ Nakhonsawan Campus, Mahidol University, Nakhonsawan, Thailand.
⁵ National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathum Thani, Thailand.

Abstract

Transformer 2 (tra 2) and fruitless (fru) genes have been proven to play a key role in sex determination pathways in many Arthropods, including insects and crustaceans. In this study, a paralog of P. monodon tra 2 (Pmtra 2), P. monodon ovarian associated transformer 2 (PmOvtra 2) and 2 isoforms of P. monodon fruitless-like gene (Pmfru-1 and Pmfru-2) were identified and characterized. The full cDNA sequence of PmOvtra 2 consisted of 1,774 bp with the longest open reading frame (ORF) of 744 bp encoding for 247 amino acids. The PmOvtra 2 exhibited a predicted RNA-recognition motif (RRM) domain and two arginine-serine (RS) regions, suggesting its function in RNA splicing. The full cDNA sequence of Pmfru-1 consisted of 1,306 bp with 1,182 bp ORF encoding for 393 amino acids, whereas the full cDNA sequence of Pmfru-2 consisted of 1,858 bp with 1,437 bp ORF encoding 478 amino acids. The deduced amino acid sequences of Pmfru-1 and Pmfru-2 exhibited highly conserved domains of Fru proteins, including Broad-complex, Tramtrack and Bric-a-brac (BTB), and zinc finger (ZF) domains. In addition, Pmfru-1 and Pmfru-2 were suggestively originated from the same single genomic locus by genomic sequence analysis. Specifically, Pmfru pre-mRNA was alternatively spliced for Pmfru-1 and Pmfru-2 to include mutually exclusive exon 7 and exon 6, respectively. Temporal and spatial expression of PmOvtra 2, Pmfru-1, and Pmfru-2 were also investigated by qPCR. The results showed that all were expressed in early developmental stages with undifferentiated gonads starting from nauplius until postlarvae. The expression of PmOvtra 2 started at nauplius stage and gradually increased from mysis to postlarvae (PL) 1. However, the expression of Pmfru-1 was low at the nauplii stage and slightly increased from protozoea to PL5, whereas the expression of Pmfru-2 maintained a low level from nauplius to mysis and then gradually increased at the PL stages. Expressions of PmOvtra 2, Pmfru-1, and Pmfru-2 were detected in various tissues including nervous tissue, gill, heart, hepatopancreas, gut, and gonads. Interestingly, the sexually dimorphic expression of PmOvtra 2, Pmfru-1, and Pmfru-2 was demonstrated in fully developed gonads in which the ovary showed significantly higher expressions than the testis. The great difference in the expression pattern of PmOvtra 2, Pmfru-1, and Pmfru-2 in the ovary and testis suggested their roles in the female sex determination in P. monodon.

Keywords: Crustacean; Sex determination; Shrimp.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Amino Acids / genetics
Animals
Base Sequence
DNA, Complementary / genetics
Female
Male
Penaeidae* / genetics

Substances

DNA, Complementary
Amino Acids

Grants and funding

This research project was supported by the Mahidol University’s Academic Development Scholarship (to Prawporn Thaijongrak), Mahidol University under the Fundamental Fund: Basic Research Fund: fiscal year 2022 (Grant no. BRF1-054/2565; to Rapeepun Vanichviriyakit), and the National Center for Genetic Engineering and Biotechnology (BIOTEC, NSTDA) of Thailand (to Anuphap Prachumwat). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.