RESUMEN
Traditionally, chimeric RNA is thought to be generated by chromosome rearrangement, and its products (RNAs and proteins) were once considered as unique features of cancer. However, with the advancement of next-generation sequencing technologies and the development of bioinformatics software tools, increasing numbers of chimeric RNAs are being identified from various RNA-Seq database. Recently, numerous chimeric RNAs were discovered in human normal tissues and cell lines, with physiological functions. Besides chromosome rearrangement, chimeric RNAs are formed by different molecular mechanisms, including trans-splicing, cis-splicing of adjacent genes. Chimeric RNAs, without chromosomal changes, are regulated at the transcriptional level, and they show specific physiological functions and regulation patterns. Their dysregulation may induce cell differentiation and tumorogenisis. In addition, chimeric RNAs also play roles in normal cell growth and/or migration, cell cycle and apoptosis, induce genomic aberration by influencing chromosome rearrangement, act as potential competitive endogenous RNA, and influence stem cell differentiation. The expression of chimeric RNAs in specific tissues and cell development stages has the potential to be used as diagnostic and therapeutic biomarkers. Histological mapping studies can improve the specificity of treatment for unique cell types, and the chimeric RNA provides a new perspective to achieve this goal. The widespread existence of chimeric RNAs suggests that they may extend the diversity of genomes in human and higher animals.
RESUMEN
ABSTRACT The Tc1/Mariner sequence was isolated and mapped on chromosomes aiming to verify the association of this transposable element (TE) and chromosomal rearrangements in Rineloricaria. Cytogenetic analysis showed that Tc1/Mariner does not co-localize with chromosomal fusion points, in addition the analysis revealed intense molecular degeneration in its DNA sequence.
RESUMEN
A phenotypically normal couple was referred for cytogenetic evaluation due to three consecutive first-trimester spontaneous abortions. Chromosomal analysis from peripheral blood was performed according to standard cytogenetic methods using G-banding technique. The husband's karyotype was normal. The wife's karyotype showed a balanced complex chromosome rearrangement (CCR) involving chromosomes 9,14, and 13. There were three breakpoints: 9p21.2, 14q21, and 13q12.2. The karyotype was designated as 46, XX, t (9;14;13)(p21.2;q21; q12.2). Fluorescence in situ hybridization (FISH) analysis with chromosome-specific libraries of chromosomes 9,14, and 13 was performed to confirm this rare chromosome rearrangement. The result of FISH coincided with that obtained by standard cytogenetic techniques.