snRNA Vs. snoRNA - Important Differences

snRNA and snoRNA are types of non-coding RNA molecules that are tiny and seen in cells. Both participate in changing RNA once the process of transcription takes place. The key difference between snRNA and snoRNA lies in the fact that snRNA participates in the alternative splicing of pre-mRNA molecules for the determination of sequence that must be translated into proteins, while snoRNA takes part in altering the tRNA, rRNA and mRNA editing and genome imprinting.

Both snRNA and snoRNA are not the same, they are different and are not even subtypes of each other. These are a class of small RNAs. They are found in the nucleolus and the Cajal bodies of the cells of eukaryotes, where they are referred to as the scaRNAs.

snRNA (Small Nuclear RNA)

  • It is one of the small RNA whose average size is about 150 nt
  • In transcript slicing typically, the snRNA offers snRNPs (ribonucleoprotein particles), in addition to some proteins forming a big particulate complex, associated with the unspliced primary RNA transcripts to moderate the phenomena
  • Often, these are found to be linked with a group of particular proteins and complexes, known as small nuclear ribonucleoproteins
  • Apart from splicing, some evidence also indicates that snRNPs operate in the nuclear maturation of the primary transcripts in the mRNAs, spicle donor in non-canonical systems, regulation of gene expression and so on

snoRNAs (Small nucleolar RNAs)

  • These are the most abundant groups of the intron-encoded ncRNAs, and are small RNAs about 60 to 170 nucleotides long, majorly seen in the nucleolus participating in the rRNA modifications
  • The majority of them are functional in the posttranscriptional alterations of ribosomal RNAs that are vital in the production of effective RNAs

Key Difference between snRNA and snoRNA

The table below depicts the difference between snRNA and snoRNA.

snRNA

snoRNA

What are they?

Small RNA seen in the nucleus of the eukaryotes taking part in the process of processing pre-mRNA

Small RNA conducting chemical alterations of RNAs

Occurrence

Seen in eukaryotes only

Can be seen in archaea, eukaryotes

Function

Processing of pre-messenger RNA (hnRNA) in the nucleus.

To guide site-specific rRNA modification.

What transcribes them?

Transcribed by either RNA polymerase II or RNA polymerase III.

Typically transcribed by RNA Polymerase II

Size

The average length snRNA is approximately 150 nucleotides

The approximate size is 60 to 170 n

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