The chromosome XII of Saccharomyces cerevisiae

The chromosome that we are studying, chromosome XII belongs to a yeast genome, Saccharomyces cerevisiae, composed by sixteen chromosomes.

This chromosome shows specific features that define him. Is formed by 1078177 bp, the longer arm measures 92053 bp and the shorter has a length of 150820 bp. It has about 534 functional genes (ORF’S) and from these genes, some are involved in replication, such as: TEN1, MEC3, EST2, SLX4, IFH1. The first one, TEN1, it’s a protein that regulates telomeric length. MEC3 it’s responsible of doing the checkpoint of the DNA damage and meiotic pachytene (one of the five subphases of prophase I) and it’s also a subunit of a heterometric complex that forms a sliding clamp (the clamp protein binds DNA polymerase and prevents this enzyme from dissociating from the template DNA strand). The gene EST2 is the reverse transcriptase subunit of the telomerase holoenzyme. SLX4 it’s an endonuclease involved in DNA processing in addition to acting during recombination and repair. The last one we refereed, the gene IFH1 it´s a coactivator and regulates transcription of ribosomal protein (RP) genes.

We researched that chromosome XII has a total of 29 autonomously replicating sequences (ARS) within:  ARS 1202, ARS 1206, ARS1207, ARS1208 (figure 1), ARS1209, ARS1210, ARS1211, ARS1212, ARS1212.5, ARS1213, ARS1214, ARS1215, ARS1216, ARS1200-1, ARS1200-2, ARS1217, ARS1218, ARS1219, ARS1220, ARS1221, ARS1223, ARS1226, ARS1238, ARS 1228, ARS1230, ARS1232, ARS1233, ARS 1234, ARS1235, that mark the initiation of replication.

Figure 1- Sequence of ARS 1208 

https://browse.yeastgenome.org/?loc=chrXII%3A24001..178800&tracks=DNA%2CAll%20Annotated%20Sequence%20Features%2CDoube_strand_break_hotspots%2CXrn1-sensitive_unstable%20transcripts_XUTs%2CScGlycerolMedia%2C3%27UTRs%2CPolII_occupancy_WT&highlight=

References

·      M. Johnston et al., 1997,  The nucleotide sequence of chromosome XII, NATURE, volume 387: pages 87 to 90

·      Saccharomyces genome database consulted in  29/10/2018 at https://www.yeastgenome.org/

                                                                                                                              

                                                                                                                                  Grupo 4.2

Ana Catarina Ribeiro

Catarina Faria

Fabiana Marques

Tânia Pontes 

Licenciatura em Bioquímica