Identification and characterization of novel alternatively spliced isoforms of the human RAB8B gene

Alternative splicing is a key mechanism that expands transcriptomic and proteomic diversity; however, its contribution to the functional complexity of many genes remains poorly understood. RAB8B, a member of the Rab family of small GTPases, plays an important role in intracellular vesicle trafficking and membrane dynamics, yet little is known about its alternatively spliced variants.

In this study, we combined in silico analyses with experimental validation to identify and characterize novel transcript variants of the human RAB8B gene. Bioinformatic analysis identified two previously unreported exons within the intronic region between exons E1 and E2, which were predicted to generate distinct transcripts with altered 5' architectures. Expression of the predicted transcripts was experimentally confirmed by RT-PCR, semi-nested PCR, and DNA sequencing, leading to the identification of two novel RAB8B transcript isoforms. Conceptual translation and comparative in silico analyses indicated that the predicted protein products of these transcript isoforms differ from the canonical Rab8b protein in amino acid length and predicted physicochemical properties. Structural modeling and molecular dynamics simulations further suggested isoform-specific differences in stability, flexibility, and conformational behavior, particularly between active and inactive states.

Our findings expand the transcript repertoire of the human RAB8B gene by identifying two novel alternatively spliced transcripts. These results provide a foundation for future studies investigating their biological functions and potential roles in cellular processes and disease.