The p-Arms of Human Acrocentric Chromosomes Play by a Different Set of Rules.
Annu Rev Genomics Hum Genet
; 24: 63-83, 2023 08 25.
Article
in En
| MEDLINE
| ID: mdl-36854315
ABSTRACT
The p-arms of the five human acrocentric chromosomes bear nucleolar organizer regions (NORs) comprising ribosomal gene (rDNA) repeats that are organized in a homogeneous tandem array and transcribed in a telomere-to-centromere direction. Precursor ribosomal RNA transcripts are processed and assembled into ribosomal subunits, the nucleolus being the physical manifestation of this process. I review current understanding of nucleolar chromosome biology and describe current exploration into a role for the NOR chromosomal context. Full DNA sequences for acrocentric p-arms are now emerging, aided by the current revolution in long-read sequencing and genome assembly. Acrocentric p-arms vary from 10.1 to 16.7 Mb, accounting for â¼2.2% of the genome. Bordering rDNA arrays, distal junctions, and proximal junctions are shared among the p-arms, with distal junctions showing evidence of functionality. The remaining p-arm sequences comprise multiple satellite DNA classes and segmental duplications that facilitate recombination between heterologous chromosomes, which is likely also involved in Robertsonian translocations.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chromosomes, Human
/
Nucleolus Organizer Region
Limits:
Humans
Language:
En
Journal:
Annu Rev Genomics Hum Genet
Journal subject:
GENETICA
/
GENETICA MEDICA
Year:
2023
Document type:
Article