Fig. 2.

Different Types of existing RNAs in living cells. RNA is either coding or non-coding. Housekeeping RNAs are fundamental and expressed primarily while regulatory noncoding RNAs are synthesised at specific phase of development or in response to some external stimuli. Various types of ncRNA include (1) lnc RNA (long non coding RNA 200nt, 5`cap and poly A tail) (2) ciRNA: circular intronic RNA (introns of protein coding genes) 3). circ RNA (circular RNA) head to tail splicing of exons. 4). eRNA (enhancer associated RNA) 5) siRNA (small interfering RNA)21-22nt. 6) piRNA (piwi interacting RNA) major role in transposon defence, germ cell development.7). miRNA (micro-RNA) 22-23nt highly conserved and plays role in post transcriptional gene silencing. 8) tRF (tRNA-derived RNA fragment) and tiRNA (tRNA-derived stress-induced RNAs) 9) YRNA functions during DNA replication in vertebrates and RNA stability. 10) TUCRNA (transcribed ultra-conserved RNAs) 11) Natural antisense transcripts (NAT) RNA 12) Telomeres RNA (TEL) is localized in clusters at the nuclear envelope. 13) ElciRNA retained intron circRNAs