Identification Of Two Novel Truncated Transcripts Of Jak2 Gene

Objective:Jak2 is one of non-receptor tyrosine kinases and plays a critical role in signal transduction via an abundant of receptors, such as erythropoietin receptor. The mutation of Jak2 gene(Jak2 V617 F, Jak2 exon12) is relative with Myeloproliferative neoplasms(MPNs). We report here two previously unknown transcripts of Jak2 gene. For screening Jak2 gene mutation in patients with MPN(mutations of Jak2V617 F, Jak2 exon12 were negative), RT- PCR was performed to amply the c DNA full-sequence of the Jak2 gene, we found the existence of two novel transcripts. In our study, we confirmed two novel transcripts of Jak2, identified the structure of RNA, predicted the protein construct of two novel transcripts, and at the same time, analyzed the expression of two novel transcripts in MPN, AL(acute leukemia), CML(chronic myeloid leukemia), healthy volunteers and other species.Methods:1. Found and identification of two new transcripts of Jak2: c DNA templates were acquired by reserve transcription with random primers. PCR was conducted with two pairs of primers F1/R1 and F2/R2 we designed for eliminating the non-special amplification.The PCR products were sequenced to identify the existence of the two novel transcripts.PCR was conducted using oilgo(d T) primers and two pairs of primers F1/R1 and F2/R2 to further confirm the two novel transcripts with “A-tail”.2. Clone and acquire full sequence of two novel transcripts.3. Identify the expression of two novel transcripts in different species by using RT-PCR.Results:1. We performed RT-PCR with using random primers and primers F1/R1 and F2/R2 to prove the existence of two novel transcripts Jak2 b and Jak2c; we performed RT-PCR using oligo(d T) primers and primers F1/R1 and F2/R2 to prove two novel transcripts Jak2 b and Jak2 c with “A-tail”; the two novel transcripts exist in healthy volunteers, it showed that the two novel transcripts were physical mature m RNA with polyadenylate tail.2. The transcript Jak2 b deletes 77 nt of 3’end exon 10 of Jak2 gene, resulting in frameshift that introduces a stop codon in the downstream exon and produces a truncated protein of 421 amino acids if translated.The Jak2 c skips the whole exon 10, leading to premature stop codon in adjacent exon 11 and producing a truncated protein of 415 amino acids if translated.3. The wild-type transcript Jak2 a exists in human, other mammals we chose and not exist in lower organisms. The two novel transcripts Jak2 b and Jak2 c exist in human and Oryctolagus cuniculuses, but there are not the two novel transcripts in Rattus norvegicuses.Conclusions:1. There are two novel transcriptions Jak2 b and Jak2 c except for wild-type transcript Jak2 a in Jak2 gene.The Jak2 b is caused by lossing 77 bp at 3’ end of exon10 of Jak2 and The Jak2 c is caused by lossing exon10 of Jak2.2. The two new transcripts Jak2 b and Jak2 c are physical and mature m RNA with Poly(A) tail and the expression of Jak2 b and Jak2 c are different in different species.