IDENTIFICATION AND EXPRESSION PROFILE ANALYSIS OF CATHEPSIN F FROM DISK ABALONE Haliotis discus discus EVIDENCING THE POTENT IMMUNOLOGICAL IMPORTANCE  

Disk Abalone is a prime organism used for consumption and for decorative items in most regions of the world. Excessive fishing and poaching has led to the lower populations, and to meet the market demands, disk abalone is farmed in many countries such as China, Taiwan, Japan, and Korea. Pathological diseases are the major cause for the loss of production. Studies related to immune related genes will lead to the discovery of novel solutions for the aqua farming industry.

The current study was based on the identification of Cathepsin F (AbCathF) from Disk abalone (Haliotis discus discus). Cathepsin F is lysosomal cysteine protease involved in essential functions as, metabolic degradation of peptides and proteins, proenzyme activation, antigen processing and protein turnover within the endosomal/ lysosomal system. Previous studies has revealed their regulatory role in MHC class II antigen processing in macrophages. Therefore, cathepsins F represent primary targets for the development of inhibitors that could block its uncontrolled activity in pathological conditions and as a result, be useful in treating certain diseases associated with excessive immune responses.

The AbCathF sequence shared a higher sequence identity (44.8%) and similarity (56.7%) with Crassostrea gigas (Pacific oyster) Cathepsin F sequence. Omnipresent distribution of AbCathF transcripts was detected in all the tissue types of healthy animals, while having the highest expression level in digestive tract, gills, hemocyte, mantle and muscle tissues. Under the pathogenic stress caused by two bacterial pathogens (Vibrio parahemolyticus and Listeria monocytogenes) and LPS, AbCathF transcription was observed to be significantly up-regulated in Gill and Hemocyte tissues (Figure: 1). Collectively, observations from current study exhibit the putative role of AbCathF in defense responses against pathogenic infections and further conforming the value in finding novel solutions for the aqua-farming industry.