Identification, classification and expression analysis of the Ras superfamily genes in the Pacific white shrimp, Litopenaeus vannamei

Abstract

The Ras superfamily of small guanosine triphosphatases (GTPases) are a large group of small GTP-binding proteins, which play crucial roles in basic cellular processes in all eukaryotes. In this study, by analyzing the gene structure, temporal and spatial expression patterns, a total of 108 Ras superfamily genes were identified in the genome of the Pacific white shrimp Litopenaeus vannamei. We found these genes included not only the classical Ras GTPase superfamily members, but also some unconventional and novel Ras GTPase proteins, which have unknown functions and unique expression patterns. All Ras superfamily genes of L. vannamei were highly conserved within the core G domain and closely related in phylogeny, but they might have two different evolutionary origins. In addition, different Ras GTPase genes exhibited distinct expression patterns in different tissues, development/molting stages and WSSV infection samples of L. vannamei, suggesting that they may have a high functional specialization, and play important roles in regulating the biological processes of cell differentiation, growth and development, immune response, etc. This study provides important clues for the structure, classification, evolution and function of Ras superfamily in shrimp.

Experimental Infection Models and Their Usefulness for White Spot Syndrome Virus (WSSV) Research in Shrimp

“…The seed quality from nauplius to postlarva can be affected by broodstock condition or maternal effects, environmental and management conditions during larviculture, as well as larval diets not fulfilling nutritional requirements [62,66]. Hence, this quality can vary significantly between shrimp batches, regardless of genetic or geographic origin, and this could in turn cause variation between study results [62,63,[67][68][69], e.g., the use of low-quality batches during a WSSV challenge experiment could hypothetically lead to a lower survival rate compared to the use of high-quality batches. This should certainly be taken into consideration when conducting WSSV challenge experiments and analyzing the outcomes.…”