What are the differences between hnRNAs, snRNAs, miRNAs, siRNAs, and snoRNAs?

Name: Problem 4, Chapter 10: Molecular Cell Biology
Uploaded: 2020-06-14T00:12:07-08:00
Duration: 5 min 47 s
Channel: John Barone
Description: What are the differences between hnRNAs, snRNAs, miRNAs, siRNAs, and snoRNAs?

step 1 So this question is asking this about RNA. And in particular, we're being asked about difference

What are the differences between hnRNAs, snRNAs, miRNAs,...

Key Concepts

snoRNA

Small nucleolar RNAs (snoRNAs) are predominantly found in the nucleolus and are involved in the chemical modification of other RNAs, particularly ribosomal RNAs. They guide the methylation and pseudouridylation processes essential for the proper maturation and function of rRNAs and other RNA molecules.

siRNA

Small interfering RNAs (siRNAs) are double-stranded RNA molecules that play a key role in the RNA interference (RNAi) pathway. They guide the sequence-specific degradation of mRNA, thereby silencing gene expression and serving as a defense mechanism against viruses and transposable elements.

snRNA

Small nuclear RNAs (snRNAs) are essential components of the spliceosome, the complex responsible for removing introns from pre-mRNA molecules. By forming snRNPs (small nuclear ribonucleoproteins) with associated proteins, snRNAs facilitate the precise recognition and excision of non-coding regions during mRNA processing.

hnRNA

Heterogeneous nuclear RNAs (hnRNAs) are the primary transcripts synthesized from DNA, encompassing both exons and introns. They serve as precursors to messenger RNAs and undergo extensive processing—including splicing, 5' capping, and polyadenylation—to become mature mRNAs ready for translation.

miRNA

MicroRNAs (miRNAs) are short, non-coding RNA molecules that regulate gene expression post-transcriptionally. They typically bind to complementary sequences in the 3' untranslated regions of target mRNAs, leading to translational repression or mRNA degradation, thus fine-tuning protein synthesis.

Transcript

00:01 So this question is asking this about rna.

00:04 And in particular, we're being asked about differences across different types of rna.

00:11 So i am going to highlight differences in roles, since the question is a little bit vague on what they actually want us to look at.

00:24 So i'm going to talk a little bit about size and then, of course, give you the written out names for the different kinds of rnas.

00:32 So first up is hnrna, and that stands for heterogeneous and nuclear, which tells you where it's located.

00:54 And these typically are pretty large rna, so we'll say they're from 300 to 3 ,000 nucleotides, and we'll make this nucleotides up here.

01:09 And in terms of rules, what we mean by heterogeneous nuclear mrna is that these are mostly pre -mrna transcripts.

01:18 So the mrna is still being made and processed.

01:22 It also could be mrnas that are no longer pre -mrnas, but they are still being processed in some way.

01:31 So they're in some sort of intermediate processing.

01:41 Next up is the small nuclear, rnas.

01:59 These are anywhere from, say, 107 to 210 nucleotides.

02:08 And these are seven molecules, seven kinds of molecules that are required in the splicing of rna.

02:33 Five of them are very commonly used.

02:35 Two of them are less common.

02:37 And they include molecules...

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