Isolation and characterization of an olive splicing factor 3B subunit 1

Abstract

Splicing factor 3B subunit 1 (SF3B1) functions in the regulationof translation and gene expression. SF3B1 forms U2 smallnuclear ribonucleoprotein complex (U2 snRNP). Splicing factors3A and 3B binds pre-mRNA at the 50site of the intron branch-ing point. This binding joins U2 snRNP to pre-mRNA. AlthoughSF3B1from various plants have been widely studied, no studieson oliveSF3B1(OeSF3B1) have been reported. This studyreports information on various aspects ofOeSF3B1 OeSF3B1 was obtained from a cDNA library we constructedfrom fruited olive leaves in December. It was putatively identifiedas a splicing factor using BLASTn, BLASTp and BLASTx. Todetermine wheter OeSFB1 was a sitoplasmic protein, SOSUIGramN was used. TMHMM was used to detect any transmem-brane domains while signal peptide analysis was conducted bySignalP. I-Tasser and Cn3D were used to generate the calculated3D structure and to compare it with experimentally generatedmodels, respectively. Nucleotide and amino acid compositionsalong with the calculated molecular weight and isoelectric point(pI) were analyzed using BioEdit and online ExPASy software.The phylogenetic trees revealed genetic relationship of oliveamong other plants based on OeSFB1. The ORF contained 1950nucleotides coding 254 amino acids that produce a 28.2 kDa pep-tide with a pI of 5.94. Alanine, valine and leucine were found athigh ratios suggesting a hydrophobicity which was also predictedby Kyte and Doolittle analysis. The AT rich property ofOeSF3B1 is not unusual comparing to most plant genes. Cellularlocalization of the gene was suggested to be in mitochondria withno signal peptide indicating OeSF3B1 could be synthesizing inmitochondria. The predicted 3D structure of OeSF3B1 was simi-lar to experimentally produced structures while some hydropho-bic pockets were predicted. Further characterization of the genewith respect to temporal and spatial expression pattern and bio-chemical function continues.